Roller Cam Specs for 340

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AJ/FormS said:
Application, application, application.
I'm guessing that yur building a street-driven hotrod, but you didn't say.
The cam for a streeter is quite different from one for a racer or for a DD or even for a weekend warrior.
Shooting for a as much power as possible, say500 hp, in a normally-aspirated 340streeter, is pure foolishness..........
When 300 in an A-body is already a tire fryer.
I'm agreeing with 273 above.
we need to know what car you have, what you'll be doing with it, and it's powertrain; plus how deep your pockets are, about how many miles a summer you are thinking of traveling, and even what gas you are willing to cough up for at every fill-up.

IMO
>your first decision should be; is hi-way travelling involved, do you have an overdrive, and if not, how high a cruise-rpm are you willing to put up with.
>and your second decision, if a 4-speed manual, is how slow do you need to drive it
And why-o-why 060 overbore?
> and the third is; if you can only fit 255s in the rear tubs, for a streeter, any more than 300hp is already frying most brands of street tires, to over 40 mph; the point being, 400hp will just fry the tires a lil further/or longer, unless you fix your traction issues first..... which gets expensive in a hurry.
> just for comparison
my 367 has had 3 cams in it since 1999, varying from about 330 hp to over 430hp. My favorite was the 330, and I would have been willing to give some of that away.
Absolute hp, on the street, IMO, is not the best goal. Nor is mega torque off the line unless you can harness it, but at least you can have fun with torque, and that allows you to use a more hiway friendly rear gear. To that end, I gotta say,
for me, with street gears,
I'll take 425 footlbs at modest rpm,
over 425 hp at some high rpm.......
every time.
I'm done with big cams, performance rear gears, hiway buzzzzzzz, and even the race-car rumble out the tailpipes. Done. Gimme a 300/330hp, 367cuber, with an overdrive, in a 3500pound ready to go driver and I'll want for nothing.
For me, overdrive is a game-changer and a must-have. I like 65=2400 or less; which, without an overdrive means a rear gear of 2.94s or less. Well, with a 340, that will be unacceptable off the line. You'd need about 416 cubes to make that come alive, lol.
With a GVod, you can run a 3.73 for the same 2400.
With an A518, it is 4.10s
With a Loc-Up, maybe 4.30s.
This one time I had a double overdrive in the which 65 was 1600, man you gotta hear your 340 singing thru full-length 3" duals at 1600! I think I could drive a million non-stop miles at 1600, lol.
Well, camming for 1600 is not gonna let your 340 stretch out any, lol. I only did that the one time, to prove a point.
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I am in the same boat, needs/wants as you.

I do have an a518 transmission. I don't need alot of low end since I am traction limited, being it's in a longbed rwd gen1 dakota.

I'm also run a much bigger tire than mosþ of rhe guys on here 29<30".

With the stock tires 215/75r15 and 3.55 rears, I only used O/D on Highways. When I went to 235/75 and for a short time 265/75 tires I basically ran with it off until 85mph.

I could (would) never run more than 3.55 if I Didn't have O/D. I'm looking for 3.73< 4.10 with the 29.5/30" tires I am looking at running.

I wouldn't run anymore rear gear than that. I want to stay between 2,100<3,000rpms on the highway.

That, and requiring P/B is making my cam choice difficult.
 
ethan santin said:
Thank you for the recommendation, is that Hughes cam a flat tap or roller? And sorry, what do you mean by my 255's being the limiting factor?
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Flat or roller take your pick, the cam I suggested is not a catalogue cam. It's just a target. Or it's a custom.

As for the tires, 255s are, well, pretty small for a stout 340. Anytime you lay on the throttle in first gear, they are likely to spin, which, if you are going around a corner, that is pretty much guaranteed to put you up on the median.

I gotta tell ya, spinning out in traffic is a lil hair raising, especially the first time. I broke a couple of aluminum wheels before I installed 275s with similar but less violent results.. For my combo, this did not stop until I fit the 295s.
Btw, when yur sliding sideways, the brakes do not work, at all. lol. But, I found that 295s on 10s at 24 psi, provide a generous contact patch, that when I stuff it in neutral, it acts like locked brakes while sliding, and then, as the speed comes down, the tires get grip, and then I can steer out of trouble.
I highly recommend that if you run 255s, don't try drifting, lol. They'll drift and slide just fine, but if you get just a tiny bit too aggressive on the throttle, you will spin you out. Along the same thinking, Do not run a VS carb. especially not a 750VS. Maybe a 500 AVS might be ok. But if you want to control the throttle in first and second gears, around town, a VS is out, and Ima thinking, a 650DP is borderline too big to learn on.
Bottom line is this; 295s can save yur azz. You need them, so you might as well start with them. and if nothing else, I would install slapper bars and if on factory springs, HD 3-way shocks on the back. Which will provide a stable/predictable platform when entering a power slide. I highly recommend that the tires be spinning already, when you begin your slide, lol. else your arms may not be able to keep up when she lets go back there, lol, sometimes it gets pretty busy in the Driver's seat.
For my Driving habits, Notta a chance could I survive on 255s on the back of my 68 Barracuda.... unless maybe I had a tired old 318 2bbl, lol. I wouldda totaled that car decades ago.
255s belong on the front, lol. But, on the Street, I find 235/60-14s adequate for some 80/90% of the time.

I'm not telling you that you should run 295s on the back.
I'm telling you that the day will come that you will wish that they were back there saving yur azz.
 
Jersey Devil said:
I am in the same boat, needs/wants as you.

I do have an a518 transmission. I don't need alot of low end since I am traction limited, being it's in a longbed rwd gen1 dakota.

I'm also run a much bigger tire than mosþ of rhe guys on here 29<30".

With the stock tires 215/75r15 and 3.55 rears, I only used O/D on Highways. When I went to 235/75 and for a short time 265/75 tires I basically ran with it off until 85mph.

I could (would) never run more than 3.55 if I Didn't have O/D. I'm looking for 3.73< 4.10 with the 29.5/30" tires I am looking at running.

I wouldn't run anymore rear gear than that. I want to stay between 2,100<3,000rpms on the highway.

That, and requiring P/B is making my cam choice difficult.
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Friend, piggy-backing onto another fella's thread is kindof like eyeballing his girlfriend; you better be prepared for trouble, lol.
I think the solution to your dilemma is pretty easy, but Ima thinking that you should start your own thread, cuz it's gonna be completely different solution to ethan's., and it would just muck up this thread.
This is my opinion.
 
ethan santin said:
Sorry sir, I hate to be this guy but I still dont know a lot (anything) about cam specs and what they mean. Could you break down what those numbers refer to?
thank you
Click to expand...
Let's just say it's real big.
 

get a off the shelf cam from Hughes. there website is easy to navigate. all the info is there for you to pick which cam suits your combo. i would get a SFT (solid flat tappet).
 
Newbomb Turk said:
Pick of decade!

Of course you could have went full AJ, written a loooooooooong reply and then suggest something like

178/186 .420/.420 114/110 because it’s a “streeter”.
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sir, that is clearly a 318 cam and we are discussing 340's

get on out of here with that nonsense!
 
I should also add it had 3.55 gears and converter was 4800. Street driven for 3 years with that combo.
 
ethan santin said:
Sorry sir, I hate to be this guy but I still dont know a lot (anything) about cam specs and what they mean. Could you break down what those numbers refer to?
thank you
Click to expand...
Hey Ethan, let me commend you for your candor regarding cam spec knowledge - it's how we learn. There's a lot to know about cams, but these are the basics. The cam in question has these specs: ".811/.801 305/295 @.050 ground on a 102" but the "decode" pertains to any cam. What you are seeing is valve lift, duration, and lobe separation angle - often just called LSA. Lets break it down further:

First is valve lift, and this particular cam has different lift for intake and exhaust: .811" int.; .801" exh. (a very high lift cam for a 340)

Next, it also has different duration for int. & exh., 305° int.; 295° exh. (a very long duration cam) Duration is the number of degrees of crankshaft rotation that the lifter is off the cam's base circle and opening or closing the valve. The "@.050" means this is measured between the lifter rising .050", and .050" before it returns to the base circle.

The 102 is also a measurement in degrees, but in this case it is ground into the cam and is the angle between the centerlines of the intake and exhaust lobes. Don't confuse this with installed centerline, which advances or retards the cam. 102° LSA is considered very "tight" centerlines and is a race only cam. The cam in question would make big power, but there would be many other very expensive engine requirements to use its full potential; like high compression ratio, ported heads, massive valve springs, heavy duty valve train parts, etc.

Plus the car would require a loose converter (high stall speed) and low (high numerically) rear end gearing because the power range will be well above idle, probably 3500 rpm or more. But it will pull to 8500 rpm or more :)

All that said, the best advice I can give for your situation is settle on your intended use, the other components of your build, and then get a cam recommendation from a reputable engine builder. Because ultimately it is all about the combination, not just picking parts based on their specs.

ctrp_0701_04_z+engine_camshaft+lobe_diagram.jpg
 
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I am doing a build similar to yours, will be using 3.55 gears and a 4 speed. I like the Hughes:

HUG SER2630ALN-10​

SB HYD RLR CAM 226/230 -110ºLSA


Or use this one for a little more upper end power with a little less low end torque:

HUG SER3034ALN-10​

SB HYD RLR CAM 230/234 -110ºLSA NEW CORE

Or use this one for a little more low end with a little less top end:

HUG SER2226ALN-10​

SB HYD RLR CAM 222/226 -110ºLSA

Cams are a compromise, if in doubt always go with the smaller cam. Too big of a cam can really kill how your engine acts and performs, a little bit smaller than an optimum cam will make a bit less power but your car will run normally and perform well. Like you could go with something like the dead cat above suggested .811/.801 305/295 @.050 ground on a 102 and your car would not spin a tire in on a dirt road with oil on top of it, it will not idle under 1200/1300 RPM's and will be a best to drive, this is assuming the valves do not hit the pistons and you do not get coil bind and all the other bad stuff that can happen with a cam like that and destroy the engine before it starts. Or you could use an OEM stock 340 4 speed cam and the car would run perfectly, have good power and be a great driver, although you are leaving power on the table.
 
TheRacerDave said:
Hey Ethan, let me commend you for your candor regarding cam spec knowledge - it's how we learn. There's a lot to know about cams, but these are the basics. The cam in question has these specs: ".811/.801 305/295 @.050 ground on a 102" but the "decode" pertains to any cam. What you are seeing is valve lift, duration, and lobe separation angle - often just called LSA. Lets break it down further:

First is valve lift, and this particular cam has different lift for intake and exhaust: .811" int.; .801" exh. (a very high lift cam for a 340)

Next, it also has different duration for int. & exh., 305° int.; 295° exh. (a very long duration cam) Duration is the number of degrees of crankshaft rotation that the lifter is off the cam's base circle and opening or closing the valve. The "@.050" means this is measured between the lifter rising .050", and .050" before it returns to the base circle.

The 102 is also a measurement in degrees, but in this case it is ground into the cam and is the angle between the centerlines of the intake and exhaust lobes. Don't confuse this with installed centerline, which advances or retards the cam. 102° LSA is considered very "tight" centerlines and is a race only cam. The cam in question would make big power, but there would be many other very expensive engine requirements to use its full potential; like high compression ratio, ported heads, massive valve springs, heavy duty valve train parts, etc.

Plus the car would require a loose converter (high stall speed) and low (high numerically) rear end gearing because the power range will be well above idle, probably 3500 rpm or more. But it will pull to 8500 rpm or more :)

All that said, the best advice I can give for your situation is settle on your intended use, the other components of your build, and then get a cam recommendation from a reputable engine builder. Because ultimately it is all about the combination, not just picking parts based on their specs.

View attachment 1716412428
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Thank you so much for this detailed reply sir, I really appreciate it.
 
273 said:
Have you narrow down what you want do or still up in the air ?
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Still sort of up in the air. I have sorta been endlessly researching how each cam spec effects performance. I really don't know how much lift is to much lift or if I should be looking at cams with more duration or less duration. I just really dont want to "over cam it" and decide on something that's to big. While I do want to drive my duster, I really want this engine to hit at least 400 ponies and if i have to sacrifice some drive- ability, thats okay. I have also begun trying to understand the world of aluminum heads and trying to decide what head is going to fit my needs. Its all very confusing.
 
ethan santin said:
Still sort of up in the air.
Click to expand...
I didn't realize the 400 hp 340 thread was yours too :)
ethan santin said:
I have sorta been endlessly researching how each cam spec effects performance. I really don't know how much lift is to much lift
Click to expand...
Lift is probably one of the easier specs to pick, You base it on your head flow curve your probably good in the .500-.550 range. LSA 110 is generally considered a good compromise.
ethan santin said:
or if I should be looking at cams with more duration or less duration.
Click to expand...
really depends on what stall and gears your willing to go with.
ethan santin said:
I just really dont want to "over cam it" and decide on something that's to big. While I do want to drive my duster, I really want this engine to hit at least 400 ponies and if i have to sacrifice some drive- ability, thats okay. I have also begun trying to understand the world of aluminum heads and trying to decide what head is going to fit my needs. Its all very confusing.
Click to expand...
Say your choices of duration (intake) range from 225 to 245 @ 0.050"

To me 225 is the middle ground cam, 200 to 219 is basically what's considered RV cams they can get away with stock stall and highway gears and have great low rpm performance, around 220-229 is where depending on engine is where torque is starting to move up the rpms enough that higher stall and deeper gears start to become necessary but still have decent low end performance above that I'd call these cams street strip cams 230-250+ and definitely need gears and higher stalls etc..
 
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To me heads cam and cr is the main trio of power, obviously you also need the appropriate intake exhaust etc.. to go a long with it.

Heads is basically the main potential (hp) that the rest is trying to bring out, so poorer flowing heads needs more cam and cr etc.. to get similar hp with better heads and should need less cam and cr etc..

So if you want smaller (within reason) cam (driveability) to reach a power goal then better heads are the key.
 
To me, somewhere in the 225 to 240 @.050 on the intake side is the sweet spot for a street car. You can go a little less for more drivability or a little more for a bit more power. Let lift fall where it may according to the manufacturer of your cam, more lift per the same duration is most of the time better, as long as you have the correct springs and piston to valve clearance. Want more lift and a little more power, use 1.6 rocker arms. Remember that your cam needs to match your converter, gearing and compression. The more duration the more you need of all of them, and the more converter, gearing, and up to a certain point compression you have the less streetable the car is.

As for heads I recently bought a set of Speedmaster heads with a set of their stainless rockers, they packaged them terribly and UPS inevitably damaged them in shipping. After looking at the heads and rocker arms and seeing that the rocker arms hit the springs, and that it was going to be a mess to get those rockers to work, and that from what I could tell any aftermarket aluminum or stainless rocker would not fit and the the geometry was all wrong I decided to return them for a refund. I have just bought a set of Trick Flow heads and I am going to get the Harland Sharp rocker arms, from what I can see these parts will fit and the geometry will be close enough for a street car to run them without any work. The Trick Flow heads and the Harland Sharp rocker arms are not cheap but they are a quality pieces that work well together.

If you want to see a Duster 340 (has a 360 in it) with a 484 lift Mopar Performance hydraulic cam (using solid lifters), Trick Flow heads, Performer RPM air Gap intake, TTI headers running 11.15 in the 1/4 and being driven on the street go look at this channel, you can learn a lot from it:

Duster Garage
 
273 said:
I didn't realize the 400 hp 340 thread was yours too :)

Lift is probably one of the easier specs to pick, You base it on your head flow curve your probably good in the .500-.550 range. LSA 110 is generally considered a good compromise.

really depends on what stall and gears your willing to go with.

Say your choices of duration (intake) range from 225 to 245 @ 0.050"

To me 225 is the middle ground cam, 200 to 219 is basically what's considered RV cams they can get away with stock stall and highway gears and have great low rpm performance, around 220-229 is where depending on engine is where torque is starting to move up the rpms enough that higher stall and deeper gears start to become necessary but still have decent low end performance above that I'd call these cams street strip cams 230-250+ and definitely need gears and higher stalls etc..
Click to expand...
HSDemon said:
To me, somewhere in the 225 to 240 @.050 on the intake side is the sweet spot for a street car. You can go a little less for more drivability or a little more for a bit more power. Let lift fall where it may according to the manufacturer of your cam, more lift per the same duration is most of the time better, as long as you have the correct springs and piston to valve clearance. Want more lift and a little more power, use 1.6 rocker arms. Remember that your cam needs to match your converter, gearing and compression. The more duration the more you need of all of them, and the more converter, gearing, and up to a certain point compression you have the less streetable the car is.

As for heads I recently bought a set of Speedmaster heads with a set of their stainless rockers, they packaged them terribly and UPS inevitably damaged them in shipping. After looking at the heads and rocker arms and seeing that the rocker arms hit the springs, and that it was going to be a mess to get those rockers to work, and that from what I could tell any aftermarket aluminum or stainless rocker would not fit and the the geometry was all wrong I decided to return them for a refund. I have just bought a set of Trick Flow heads and I am going to get the Harland Sharp rocker arms, from what I can see these parts will fit and the geometry will be close enough for a street car to run them without any work. The Trick Flow heads and the Harland Sharp rocker arms are not cheap but they are a quality pieces that work well together.

If you want to see a Duster 340 (has a 360 in it) with a 484 lift Mopar Performance hydraulic cam (using solid lifters), Trick Flow heads, Performer RPM air Gap intake, TTI headers running 11.15 in the 1/4 and being driven on the street go look at this channel, you can learn a lot from it:

Duster Garage
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Thanks for the link sir, Is that your channel? Ive watched those videos many times, they have been an excellent resource.
 
273 said:
To me heads cam and cr is the main trio of power, obviously you also need the appropriate intake exhaust etc.. to go a long with it.

Heads is basically the main potential (hp) that the rest is trying to bring out, so poorer flowing heads needs more cam and cr etc.. to get similar hp with better heads and should need less cam and cr etc..

So if you want smaller (within reason) cam (driveability) to reach a power goal then better heads are the key.
Click to expand...
Thanks for all your info 273, its all been very helpful.
 
ethan santin said:
Now what exactly constitutes a poor flowing head?
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One that flows less especially if they have similar port size, I don’t mean poor as in bad per se, just less potential. And even though we generally talk about peak flow it’s about the whole flow curve especially between.300 to .550/.600 lift your generally not gonna have more lift than that especially for a 400 ish hp engine.
ethan santin said:
Is a head rated at 171cc flow worse then one ratted at 190cc?
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The bigger port should flow more but don’t always.

“Or could they both be a suitable head just for different applications.”

They kind of are.

What I mean say stock 340 x heads and 240 cam and 10:1 cr with Air-Gap and headers = around 400 hp. If you wanted to still make the same hp but with smaller cam say a 230 your probably gonna need a head or make the stock heads flow around 20 cfm more.
 
273 said:
One that flows less especially if they have similar port size, I don’t mean poor as in bad per se, just less potential. And even though we generally talk about peak flow it’s about the whole flow curve especially between.300 to .550/.600 lift your generally not gonna have more lift than that especially for a 400 ish hp engine.

The bigger port should flow more but don’t always.

“Or could they both be a suitable head just for different applications.”

They kind of are.

What I mean say stock 340 x heads and 240 cam and 10:1 cr with Air-Gap and headers = around 400 hp. If you wanted to still make the same hp but with smaller cam say a 230 your probably gonna need a head or make the stock heads flow around 20 cfm more.
Click to expand...
Gotcha, thank you for answering all my questions, i really appreciate it
 
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