'75 360 Rebuild, Cam?

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70DusterBob

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I have a 70 Duster this engine is sitting in. 727 with 9.5:1 pistons. The Rear Gears are 3:55's. The tires are at 27" Dia. right now, but may go down an inch or two. These are 60 Series, will be putting on 50 Series in place of them, 15" Rims. The car, with me and tools weighs about 3,200lbs.

I just got an AirGap Eddie, will be using my Holley 600 CFM 4150 (Mech) and standard headers, Electronic Ignition/Better than Stock. I am not a cam expert, but I would like to have a hydraulic roller cam as big as I can get for the street. Don't plan on using the Duster as a daily driver, just for fun. But I don't want to only get 8mpg either. It gets 12 or so at 65 on the highway now with the above and a Performer intake and very mild cam. I do understand I will lose mpg, but don't want it to take a serious dive. What is a reasonable expectation for mpg with a decent cam?

Anyone have a suggestion for lift and duration? I would like to have a cam mfg & prt# if you have one. I "think", not sure, that buying a kit would be most economical, but I notice not all mfg's offer one for every cam. As long as the required spring prt numbers and other assembly numbers are available, I can find them or ask the mfg if I have a cam mfg and prt#

Thanks...
 
BTW, just checked the specs on that cam # and it looks great, everything lines up spec wise.

Thanks
 
How much does the porting cost?
I can not answer that because porting costs vari machine shop to machine shop, state to state, region to region, but, I can offer a solution. You’ll just have to add the cost of shipping your heads there and back unless you can drive there for fun and write off the costs as vacation..... LMAO!

Shady Dell Speed Shop
Or
Modern cylinder head

Both have excellent CNC programs.

Check around your area for a good recommendation and ask the machinist for price quotes and ask what specifically is done to the head and what you should expect back. Have a good chat with the machinist. Tell him your new to this. Speak with him like he is your buddy and you should be just fine.

Everybody is in the same area for cost vs work done and end results.
 
BTW, just checked the specs on that cam # and it looks great, everything lines up spec wise.

Thanks
Your welcome. The wife and I both like the build. I did the .030, 360 with zero sexy Hyper slugs from Federal Mougal with stock Edelbrock heads, (you’ll find those springs weak for a hyd. lifter) 600 AFB, Weiand Stealth, TTI stem to stern exhaust @ 2-1/2, a 904 w/shift kit and a Pro Torque restalled factory converter @ 2300-ish. It could use a little more but that was my call. Excellent street manors, good top end pop for a small cam. The head porting and 1.6 rockers coming soon.
All in a ‘67 Cuda FB.
 
Hey Rob,

Thanks for both replies. I also have 2-1/2" exhaust/headers. It may take a while, but I will let you know how it turns out.
 
Got a quote from a local shop, about $750 I believe, if my poor memory serves me today, to port the heads. They are a pro shop, not fly by night. Does that sound about right? It would be worth it for the output increase.
 
Depending on what is done, YEP!

Here is what Shaddy Dell is doing for $750.
Remember the added cost you have with shipping to and from other out of state places. It is approx. a little over a $1 per pound.

EDELBROCK HEADS:

STAGE 1 PORT WORK: $325

Details: Stage 1 porting consists of an intake and exhaust bowl blend. We hand blend the the bottom cut of the valve job to the bowls going approximately 1 ½”-2” down into the bowl. On the exhaust side this includes hand radiusing and ovaling of the exhaust seat area underneath the 45* seat angle. On the intake side we “chatter” the valve seat under the bottom 60* cut with a carbide to help break up the wetflow as it crosses the valve seat. The exhaust port will also get the short turn and ST corners radiused. The intake port will get gasket matched, and the pushrod pinch area will be opened up to .950” wide. The rest of the intake ports and exhaust ports will remain untouched, in as cast state. NO chamber work of any kind is performed.

STAGE 2 PORT WORK: $550
Details: Stage 2 porting consists of Stage 1, plus: Intake runner head bolt bulge will be eliminated, intake short turn will be radiused and widened slightly. Combustion chambers will be de-shrouded to 4.08” Bore size, fully sand rolled with 120 for an ultra fine finish.
The rest of the intake runners and exhaust runners will remain AS CAST, with no blending/shaping or sand roll work performed.

STAGE 3 PORT WORK: $750
Details: Stage 3 porting consists of Stage 1 and 2, plus: Intake and exhaust runners will be fully blended/shaped, every inch of all ports/chambers will be touched with a carbide/sand rolled for maximum flow and surface finish. This is maximum flow 2.02” port job we can do on an Edelbrock head, and is the most popular stage of port work we do.

STAGE 3 PORT WORK

LIFT------IN/EX
.100"----77.6/N/A
.200"--144.9/112.2
.300"--204.3/151.8
.400"--255.3/189.8
.450"--276.0/199.1
.500"--286.0/201.9
.550"--292.2/206.3
.600"--297.4/208.4

IF, you were to take full advantage of these flow numbers with a max or near max effort, you would have the ability
(On paper at least, your combo will have to be stout!)
to make more than 600 hp.

The cam is small and the additional HP amount I can not verify.
With a 1.6 rocker, you will be lifting the valve to approx. .573/intake.

For what it's worth, I think my current set up runs very well. The extra work may not produce huge results or what you expect. This extra work is elective.
 
Have you considered a solid lifter camshaft?
On the street, with 9.5Scr,an automatic,3.55s, and mileage a consideration,
IMO
you need to keep the advertised duration as short as possible,commensurate with putting the power closer to where to are gonna be actually driving at.
400hp is nice and all, but with your gears it doesn't arrive until about 50 mph.So now a big TC will get you past the problem, but there goes the fuel-mileage.
A modest duration solid lifter cam can give you the bottom end efficiency for actually having fun without having to floor it all the time.
___________________________
I got greedy and installed a 292/292/108 and regretted it almost right away. I swapped it out for a 270/276/110 and was way happier. That 276 was a 223@050, pretty small, but dynomite fun with 3.55s
 
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Have you considered a solid lifter camshaft?
On the street, with 9.5Scr,an automatic,3.55s, and mileage a consideration,
IMO
you need to keep the advertised duration as short as possible,commensurate with putting the power closer to where to are gonna be actually driving at.
400hp is nice and all, but with your gears it doesn't arrive until about 50 mph.So now a big TC will get you past the problem, but there goes the fuel-mileage.
A modest duration solid lifter cam can give you the bottom end efficiency for actually having fun without having to floor it all the time.
___________________________
I got greedy and installed a 292/292/108 and regretted it almost right away. I swapped it out for a 270/276/110 and was way happier. That 276 was a 223@050, pretty small, but dynomite fun with 3.55s

This does interest me, but I was under the assumption that solid lifters have to be adjusted now and then. Is that right? If so, is there a hydraulic shaft that would resemble this type of performance? I do prefer bottom end over top. I have plenty of top and top end is not so much what I like or am after. I mean I like a full pull, but the 360's seem to do great up top, and lack bottom end. It would be great to enhance the bottom and not lose any off the top if not gain some on the top too!

If I got the heads ported a good amount, how would that effect my mileage?

Thanks
 
Depending on what is done, YEP!

Here is what Shaddy Dell is doing for $750.
Remember the added cost you have with shipping to and from other out of state places. It is approx. a little over a $1 per pound.

EDELBROCK HEADS:

STAGE 1 PORT WORK: $325

Details: Stage 1 porting consists of an intake and exhaust bowl blend. We hand blend the the bottom cut of the valve job to the bowls going approximately 1 ½”-2” down into the bowl. On the exhaust side this includes hand radiusing and ovaling of the exhaust seat area underneath the 45* seat angle. On the intake side we “chatter” the valve seat under the bottom 60* cut with a carbide to help break up the wetflow as it crosses the valve seat. The exhaust port will also get the short turn and ST corners radiused. The intake port will get gasket matched, and the pushrod pinch area will be opened up to .950” wide. The rest of the intake ports and exhaust ports will remain untouched, in as cast state. NO chamber work of any kind is performed.

STAGE 2 PORT WORK: $550
Details: Stage 2 porting consists of Stage 1, plus: Intake runner head bolt bulge will be eliminated, intake short turn will be radiused and widened slightly. Combustion chambers will be de-shrouded to 4.08” Bore size, fully sand rolled with 120 for an ultra fine finish.
The rest of the intake runners and exhaust runners will remain AS CAST, with no blending/shaping or sand roll work performed.

STAGE 3 PORT WORK: $750
Details: Stage 3 porting consists of Stage 1 and 2, plus: Intake and exhaust runners will be fully blended/shaped, every inch of all ports/chambers will be touched with a carbide/sand rolled for maximum flow and surface finish. This is maximum flow 2.02” port job we can do on an Edelbrock head, and is the most popular stage of port work we do.

STAGE 3 PORT WORK

LIFT------IN/EX
.100"----77.6/N/A
.200"--144.9/112.2
.300"--204.3/151.8
.400"--255.3/189.8
.450"--276.0/199.1
.500"--286.0/201.9
.550"--292.2/206.3
.600"--297.4/208.4

IF, you were to take full advantage of these flow numbers with a max or near max effort, you would have the ability
(On paper at least, your combo will have to be stout!)
to make more than 600 hp.

The cam is small and the additional HP amount I can not verify.
With a 1.6 rocker, you will be lifting the valve to approx. .573/intake.

For what it's worth, I think my current set up runs very well. The extra work may not produce huge results or what you expect. This extra work is elective.

Yeah, the shipping would exceed the price of the work I'm afraid if I sent them up there, especially if they had to go both ways. But I am interested in the Lift----IN/EX numbers. Are you referring to the lift of the cam? I don't understand. I know the springs need to handle the lift and the heads need to be cut to handle the different types of springs that need to handle the different lifts. Is that what this list is referring to?

600 would be about 2x what I'm getting now. Would I be getting half the mileage on the highway? Or does it make the engine more efficient as well as increase hp?

Thanks
 
Bad mileage. I don’t think so. You could loose some mileage. It is possible. It’s a catch 22. The stock cylinder heads will only breath in so much. The most they’ll breath in is only as much as they flow and the amount of air and fuel it breaths in is limited to the duration and lift of the cam. Increaseing breathing ability will consume more air and fuel. But only as much as the gas pedal is pushed & the cam opens the valve in duration and lift. Just a slight bit more.

This increases efficiency of the cam and the power it makes with the available cam specs. Or in other words, more power without using a bigger cam which for sure will consume more fuel.

Mileage will hardly be effected. I think you’ll suffer a mileage loss due to stepping on the throttle harder more often. The throttle opening amount will not change a lot. You’ll make more power at a lower rpm which is a slightly more closed throttle position because it is more efficient. Because your making more power at a lower rpm, you should still get good mileage. Though a cam of this size, mileage will suffer a little. The wife reports about 16 on the average. I don’t have any straight answers on exactly what the car is getting due to several factors starting with inaccurate speedometer & a inaccurate wife with inaccurate mileage divided by fuel pumped in at the pump. She drives the Hwy. mostly.

The bad gas mileage most cars suffer from are due to big cams, poorly balanced combinations, high stall and gears, I’ll timed and poor ignition, I’ll tuned carburation. In your particular combo, one of the best bang for the buck mods you can afford yourself is an overdrive transmission. There are other tricks to pull as well. A small carb is good for mileage but bad for top end. The use of a spreadbore carb like a TQ or QJ, or fuel injection, multiple spark ignitions, wider spark plug gaps, variable duration lifters.

I don’t know what you would consider bad mileage or what is acceptable for you. Dropping the cam duration 10*’s or more would be a help. So would changing the rear end ratio to 2.76. But then I say, where’s the fun? With those two changes alone, you might as well just slide in a 2bbl carb and stock engine.

As her car sits now, I wouldn’t have a problem driving a few hundred miles or hours.

I’ll report back what she tachs at Hwy. speeds. IIRC, it’s 3K.
 
But I am interested in the Lift----IN/EX numbers. Are you referring to the lift of the cam? I don't understand. I know the springs need to handle the lift and the heads need to be cut to handle the different types of springs that need to handle the different lifts. Is that what this list is referring to?
The intake and exhaust numbers listed is what THAT head porter gets on a fully ported head porting. That’s what the head will take in (air and fuel at wide open throttle. Not at part throttle when your cruising the Hwy.
You are correct about the bigger cam lift needing springs and the heads cut for the springs is partially correct because that is dependent on the spring itself.

The cam lifts the valve to .538 with a 1.5 rocker.
With a 1.6 rocker, lift goes to .573.
That would require in many cases a new spring over the listed one at the lower lift.
 
Would I be getting half the mileage on the highway? Or does it make the engine more efficient as well as increase hp?
Question 1. I don’t know what your getting now and that answer
Is basically impossible to answer though in general, it is a “NO!”
Answer 2, Yes, but..... I did answer it above without realizing it.
 
Question 1. I don’t know what your getting now and that answer
Is basically impossible to answer though in general, it is a “NO!”
Answer 2, Yes, but..... I did answer it above without realizing it.

Thanks Rob,

You seem to have answered all my questions quite well. I do understand about the more efficient engine with the ported heads would not significantly decrease mileage due to the fact that the engine is breathing easier. Seems like a lot of the power at low end and cruising that it would be making would be from the absence of having to suck the intake through a small straw as it were. Now on the floor, yeah, it will suck more intake, producing more power due to the fact that it "gets" more air through the larger straw.

I was getting, the last time I checked, with a 750 4150 set to dump fuel was 12 on the highway. I don't want to go under 10 if possible. I had large orange cams for the acc. pumps, but smallish jets. I had an adjustable secondary linkage that would open the secondaries at 70mph, so at 65 I was running off the primaries. It was inefficient, and I got more hp when I switched to my 650, using the same set up with the orange cams and the adjustable sec. linkage, much to my surprise. It is much more efficient. The odometer was not working for a while, the speedometer cable was snagging, so I fixed that. Now I can check mileage again, with the 650, but there are metal flakes in the oil, so I have to do a rebuild. I do want to port the heads as much as possible, and put the cam listed in your first reply. I think that would work best for what I'm looking for, and fits the engine, tires, exhaust, intake, ported heads, etc, well.

My last question is carburetor size. I'm sure I could just experiment and put the 750 on it to see what it does vs the 650, but would you say the engine could handle the 750 with the cam and ported heads? I hope so. If so, what would be a good jet size to start experimenting with? I am in Tx, hot as hell in the summer, and mildly cool in the winter. Just upgraded the distributor a bit so that should help too.

Thanks,
Bob
 
The engine IMO could use the 750 just fine. It would be more for top end RPM though. Are you there often?
I’m not sure what to tell you as far as jet is concerned because I don’t run a Holley. Or have for about 30 years now. Except a short stint a while back on a thread I did. (‘06, 318 on the cheap rumblefish's Duster project ) Long story, broke the base plate. I’m not not biased on Holleys.

At that time, the (318) engine was tested to a few bolt on parts and a cam 10*’s smaller with 3.21’s. Both the Holley (1850/4160-600cfm) and Carter (600afb) got the same mileage. 17/18 Hwy. Right now, I’m running the Edelbrock 600 AFB currently. I had the AVS model on top. Both very smooth.
 
I have a 70 Duster this engine is sitting in. 727 with 9.5:1 pistons. The Rear Gears are 3:55's. The tires are at 27" Dia. right now, but may go down an inch or two. These are 60 Series, will be putting on 50 Series in place of them, 15" Rims. The car, with me and tools weighs about 3,200lbs.

I just got an AirGap Eddie, will be using my Holley 600 CFM 4150 (Mech) and standard headers, Electronic Ignition/Better than Stock. I am not a cam expert, but I would like to have a hydraulic roller cam as big as I can get for the street. Don't plan on using the Duster as a daily driver, just for fun. But I don't want to only get 8mpg either. It gets 12 or so at 65 on the highway now with the above and a Performer intake and very mild cam. I do understand I will lose mpg, but don't want it to take a serious dive.
What is a reasonable expectation for mpg with a decent cam?

With 3.55s and 27s, your hiway rpm @65mph,will be 2800 to 3000 depending on TC slip, grade and wind. This is the first and worst problem to achieving fuel mileage. Rpm just kills it. You only have 2 options; 1) an overdrive, and 2) less rear gear.
I read in a book once that for every 2% that you can reduce your cruising rpm, you will gain 1% in fuel economy. IDK if that is true, but one time I installed a combo that reduced my final drive from 3.55 to 1.97, reducing my cruise rpm @65, from ~2900 to ~1600 which is a loss of 45%....... so should get me in increase of 22.5 % in mpgs. Well it did waaaaaaay better than that.

So bottom line is gears make the second biggest difference to economy; the first being driver-control. Third used to be the loose TC but I hear things have gotten better, but it's probably still better to have a stall lower than your cruise rpm.
But the hitch in this program is that with only three gears in the trans, if you lower the TM in the rear , then you quickly run outta gear for blasting off with, unless your combo is built with lots or low-rpm power in the engine.
So whenever fuel economy is a consideration, the WHOLE COMBO has to be considered. When power with economy is considered,normally aspirated, it gets doubly hard,and sacrifices have to be made.
So with that in mind, and assuming your pockets are deep, here is something to think about.
Scenario #1
3.23s are 10% less rpm at cruise, upping your cruise-economy ~5% or from 12 to 12.6mpg. Lets build a combo around those 3.23s. The first thing you are gonna need to do is ;
swap out the 727 for an A998wide-ratio-non-loc-up, with gear ratios of 2.74-2.54-1.00 . This will restore your first gear TM from 8.7(with the 3.55s) to 8.85(with the 3.23s), so you actually gained a wee bit there. Your cruise rpm falls from 2800/3000 to 2600/2740; about 200rpm.
But we have a bit of a problem; the splits on the 727 were .59-.69, and on the A998 trans, the splits are; 56-.65.... so your engine is gonna have to work a tad bit harder at the extremes of the power band. For a 360 this is only a problem if you select the wrong cam for your compression ratio. And you are not gonna post a low ET with this combo no-how. You can still post a good mph, but would have to be content with being just a tad less quick.
Now we get to the engine/stall/cam
A true 9.5 Scr (as opposed to 9.5 rated pistons), is gonna be a bit of a challenge . To reach it's upper potential for pumpgas and iron heads, @160psi cylinder pressure, would require an ICA of 56*..... which is a pretty small cam. The upside to this is the bottom end will be very strong. So strong that you could run a TC with as low a stall as perhaps 2200.
However, our cruising rpm with 3.23s will be say 2600 lightly loaded, so we can lose a bit of cylinder pressure and not miss it with a 2600TC. This will allow us to run a tad bit more cam, say an ICA of 60* for 155psi.
You lost some cylinder pressure and ultimately a wee bit of peak power, but with the 2600, you will have plenty enough to have fun with at lo rpm.
So if you are with me so far, then all we have to do is find a fast rate of lift cam with a 60* ICA.
Well, as it happens, this ICA can be found on all the most popular 268/110 cams,lol
But here is the rub; there are fast 268s and there are turd 268s so buyer beware.
A fast solid flat-tappet 268 might have 38* ramps making your 268 a 230@.050 which is a heck of a powerhouse street cam.
A turd 268 might have (I heard of one) 76* ramps, making your 268 into a 192@.050 kindof like a 318cam with attitude. But more typically
a hydraulic roller might have 58* ramps making your 268 into a 210@.050 cam, kindof like a 340cam.
A flat-tappet hydraulic might turn your 268 into a 220@.050 middle of the road cam.
All of these could have the magic 60*ICA.
Now armed with this knowledge, you could back up the bus and go for the previous 56* ICA and just grab the fastest solid lifter cam you can find.
But there is another problem. solid lifter cams are rated differently than hydros and you need to order the next bigger cam usually, to get the NET 56* ICA that you want, because some of the duration is lost in the lashing. And this brings up another little tidbit; the lash plays a huge part in the actual ICA, and the greater the lash spec the more duration is lost. So it sorta sounds like a crapshoot and it sorta is.
So then your search is for a fast-rate cam, with a tight-lash spec and go one size bigger than you planned on.
And that brings us to LSA the lobe separation angle.
Generally, a wide ratio trans requires a wide LSA cam and vice versa. This is to satisfy the powerband requirement of the trans.
Wide LSAs start at about 115. And tight ones at 106 with 110s being the default will-work-in-either. In the above examples I used 110s and 4*advanced, only because this is off-the-shelf stuff.
The thing is; two otherwise identical cams, but one with a 108LSA and the other a 114; the 108 will make more specific power than the same cam ground on a 114LSA. However the 114 will have a slightly wider powerband.
This only matters to you on the 2-3 shift...... which with 3.23s might occur at 86mph. As a streeter, how often do you expect to be racing somebody up there that you would need to be concerned with this? With the proper cam and 15" street tires, the proper combo will spin the tires to 40, or 50 mph, so the LSA could be tightened up, to net you a few more rpm on the cam and thus a tad more power...... but at this power level I wouldn't worry much about it, so long as you stay away from anything over 112...... If we're still on the same page.
solids require periodic lashing to maintain the proper ICA and thus the power. But solids allow the engine to make a bit more power.
Ok so bottom line now is still same as it was earlier. Get the fastest rate of lift solid lifter 268 you can lay your grubby hands on.......... with the previous combo worked out.
That takes care of the power.
Unfortunately, the fast rate 268/276/110 cam comes with a penalty, the overlap at advertised, is 52*. Overlap is the time in the workings of the engine during which BOTH valves are open to some degree. With both valves open, the intake manifold is connected to the header pipes. And headers are designed to yank on the atmosphere during this time, initiating Air/Fuel flow before the falling piston actually gets to work on that. This effect is tuned by the header manufacturer to occur over a specific usable rpm range, usually higher in the rpm range. But it is still working at idle and still working at the lower rpms to some degree.Soooooooo, guess what that does to fuel economy. Hyup gas is going right out the tail-pipe.
But something else is going on. The later your ICA is, the further up the cylinder the piston is able to travel, before the intake valve actually closes. Sooooo it is possible for the piston to push some of the just inhaled AF charge, back into the intake. This effect is most noticeable at idle, and is part of why the idle-vacuum drops as the cam gets bigger. As the rpm increases, there is less and less time for this phenomenon to occur, and eventually the vacuum rises to a peak value, with a street cam usually around 2000 or a little higher rpm. So guess what this does to fuel economy.Nothing good that's for sure.
So that was scenario 1 for you.
Scenario 2
is to keep your 3.55s , and keep your 727, and re-examine the cam choices, the cylinder pressure, and the TC. But one thing remains the same; with a true, measured,9.5Scr, on the start-line, you will have to play the balancing game between gear,Stall and cylinder pressure; and for performance, economy usually is the loser, no matter how fast the rate of lift on the cam is.
 
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OMFG (o my freakin goard, or head)
what a long winded reply of freakin babble and babble on top of babble.

You could have made that a hell of a lot shorter!

WTF?!?!?! G’s Crist man!

Let me show you how....

You can get better mileage with lower gears of X.xx according to AJ by simply turning less rpm and consuming less fuel doing it.

Now introduce the math in a simple manor and be done with it!

Goooooooooo lllllllllllllllllyyyyyyyy

Hey AJ, look at this....

Here is a hell of a trick, use Rhodes lifters to reduce your cams duration. The upper models of the variable lifter allow you to dial in manually up to 20*’s or duration @ .050 less than the cams original duration.

224 to 204, barley bigger than a stock cam in some cases.

The variable duration lifter returns full lift & duration at approximately 3K. They have been around for a very long time.

Get biggie with dat AJ!
:icon_fU::elmer::)
 
With 3.55s and 27s, your hiway rpm @65mph,will be 2800 to 3000 depending on TC slip, grade and wind. This is the first and worst problem to achieving fuel mileage. Rpm just kills it. You only have 2 options; 1) an overdrive, and 2) less rear gear.
Scenario #1
3.23s are 10% less rpm at cruise
And that’s all you needed to say....
But it isn’t try. There’s more than one way to skim the mileage cat.






Scenario 2 is to keep your 3.55s , and keep your 727, and re-examine the cam choices, the cylinder pressure, and the TC. But one thing remains the same; with a true, measured,9.5Scr, on the start-line, you will have to play the balancing game between gear,Stall and cylinder pressure; and for performance, economy usually is the loser, no matter how fast the rate of lift on the cam is.
You act like this is a problem all the time but hot rodders have been running this combo longer than your Alive, GET OVER IT!
 
Thanks Rob,

You seem to have answered all my questions quite well. I do understand about the more efficient engine with the ported heads would not significantly decrease mileage due to the fact that the engine is breathing easier. Seems like a lot of the power at low end and cruising that it would be making would be from the absence of having to suck the intake through a small straw as it were. Now on the floor, yeah, it will suck more intake, producing more power due to the fact that it "gets" more air through the larger straw.

I was getting, the last time I checked, with a 750 4150 set to dump fuel was 12 on the highway. I don't want to go under 10 if possible. I had large orange cams for the acc. pumps, but smallish jets. I had an adjustable secondary linkage that would open the secondaries at 70mph, so at 65 I was running off the primaries. It was inefficient, and I got more hp when I switched to my 650, using the same set up with the orange cams and the adjustable sec. linkage, much to my surprise. It is much more efficient. The odometer was not working for a while, the speedometer cable was snagging, so I fixed that. Now I can check mileage again, with the 650, but there are metal flakes in the oil, so I have to do a rebuild. I do want to port the heads as much as possible, and put the cam listed in your first reply. I think that would work best for what I'm looking for, and fits the engine, tires, exhaust, intake, ported heads, etc, well.

My last question is carburetor size. I'm sure I could just experiment and put the 750 on it to see what it does vs the 650, but would you say the engine could handle the 750 with the cam and ported heads? I hope so. If so, what would be a good jet size to start experimenting with? I am in Tx, hot as hell in the summer, and mildly cool in the winter. Just upgraded the distributor a bit so that should help too.

Thanks,
Bob
You are sharper at tuning ,THAN Most...
A decent almost fire breathing cam grind..Crower 31916... needs a mild converter, real world 9 to 1 compression, at minimum 3 55 gears... minimum loss ,on street abilities ,maximum on torque. ( a air gap,would be nice ,any good dual plane works here..)....
 
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