I'd like your thoughts on this 360

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318willrun

Utube channel 318willrun
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Many of you know me, I entertain myself with weird projects. This one is close to going to the track. I'd like to hear what you think it will do. Here is the project:
  • '76 Duster bought here on FABO :D
  • 8 1/4 rear 2.45 gears one legger :thumbsup:
  • 235/60 15's on the back
  • stock 904/stock converter
  • factory exhaust manifolds with duals
And now the 360....
Stock remanufactured long block from auto parts store. Not the way to go, I know, but I got it off of CL cheap (into long block about 400 bucks) never fired, but had sat a few years. I put a 4bbl on it, and it has this cam https://www.summitracing.com/parts/crn-693902/overview/ (less than a stock 340, it was in on the engine deal)
Nothing done to enhance anything. No porting, no raising the compression, no nothing.

Question is, what will it run in the 1320 ?? Your thoughts? :thankyou: Factory 360 Dusters ran 15's according to all the documents I could find. I couldn't find the gears they were tested with, but I assume better than 2.45..
 
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If it's a stock 360 with 2.45 gears, I'd be surprised if you could crack 15.50. If mid 14's are what you're trying to get to, a 3.55 suregrip rear end might be enough.
 
this going to be interesting but i think the 2.45:1 gears are the deal breaker.
That is a great "street cam" for a sm blk with stock converter, 14" tires and 3.23.It pulls very hard from 800 rpm up to 4800.
 
If it's a stock 360 with 2.45 gears, I'd be surprised if you could crack 15.50. If mid 14's are what you're trying to get to, a 3.55 suregrip rear end might be enough.
I'm not trying to get to any number, but trying to get the car timed/tuned the best i can so it can run what it can. You may be dead on at mid 15's, it's what the factory 360 Duster's ran (all over the 15's, depending who tested), and I'm pretty sure they probably had 3.21 - 3.55's. I'm just now starting to test/tweek. Motor has been in the car but sat for close to a year while I did some work to the dash here and there. Now I'm working with it, seeing what it likes, and I hope to make a trip down the strip in 2-3 weeks.

P.S. - I love this kind of stuff.... :)
 
The Car Craft Duster 360 ran 14.6s with 3.55s stock.

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318Will. Now I'm watching your 360 thread. Hahahaha. It would've been nice to see what my 318 was capable of but it looks like I'm on the 360 train now. Hope to get mine into the 14s. Good luck with the build bro.
 
318Will. Now I'm watching your 360 thread. Hahahaha. It would've been nice to see what my 318 was capable of but it looks like I'm on the 360 train now. Hope to get mine into the 14s. Good luck with the build bro.
thanks! I know you were disappointed, but the 360 is a better build. 42 cubes will pay dividends.
My 360 project will be about worst case scenario. It will be interesting to see if this Duster will run a better time than my low dollar 318 Duster.
We'll know here real soon! :D
 
Well those 2.45s will get you about 65@5400 in first. Then at the shift, the Rs will drop to 59% or 3200ish, from which she will have to pull up to near 80/85 mph. So that's a tough slog. 82 will be about 3900. But if she makes it there; 82 is 21.6 seconds with unlimited suspension, soooooooo
But just maybe she'll creep up to 90mph@4300. And 90mph is 16.6 with unlimited suspension.
You got two ,maybe three, problems. And you already know their names.
The first is that cam.It will drop your cylinder pressure into the basement. See if you even have 125psi. Part of that cam's problem is the slow ramps 204 from 262 is 58 flipping degrees. The other part is that with a stock compression, this cam sucks the Dcr down,down,down to maybe 6.7
 
Well those 2.45s will get you about 65@5400 in first. Then at the shift, the Rs will drop to 59% or 3200ish, from which she will have to pull up to near 80/85 mph. So that's a tough slog. 82 will be about 3900. But if she makes it there; 82 is 21.6 seconds with unlimited suspension, soooooooo
But just maybe she'll creep up to 90mph@4300. And 90mph is 16.6 with unlimited suspension.
You got two ,maybe three, problems. And you already know their names.
The first is that cam.It will drop your cylinder pressure into the basement. See if you even have 125psi. Part of that cam's problem is the slow ramps 204 from 262 is 58 flipping degrees. The other part is that with a stock compression, this cam sucks the Dcr down,down,down to maybe 6.7
I doubt I will shift this at 5400. And yes, as you pointed out, this is set up to fail. However, for what little I've messed with it, I've been impressed with the low end (to my surprise!). And yes, it will sound like an old GM powerglide... LOL
 
i wouldn't have thought a duration of only .204 would bleed off compression?I have used that cam
and the lo rpm torque was very strong.
 
i wouldn't have thought a duration of only .204 would bleed off compression?I have used that cam
and the lo rpm torque was very strong.
You are correct on the second part of your statement. No cam card numbers can stand up and defy what actually happens when the car is floored. I too have experienced that the low end with this cam is the most impressive part so far (always keeping the project in mind to keep it real when I say impressive).
 
Maybe I'm preaching to the choir. Maybe I am wrong.
But this cam has a dual personality. It has slow-rpm characteristics like a 262, so below 2000 or so the late closing intake is a problem. Sure if you have a 2400 TC, and never operate down there, it's no big deal when you floor it; cuz then personality #2 takes over. But then it's,(to ME) a total waste of 2400rpm of the powerband, where probably 80% of my driving occurs, and I have a clutch, so in day to day operation,I demand torque from idle on up. If I need power, that is easy; just rev it up and go. But to me this rpm range from Idle to 3000 is extremely important. That's where my engine lives. This above cam totally wastes about 3 sizes of cam at off idle and this decreases to 2 cam sizes by about 1500/1800, and then 1 cam size to about 2200. So yeah, in an automatic with a 2400TC maybe no big deal, I'll concede the point. Just don't stick it in a low-compression teener with a clutch, cuz you'll be sounding like a Mustang.
But I guess if I had a cam like that, new in a box, I could make a quick sale right here on FABO,lol.
But If I was shopping for a 262, I'd be wanting one about 220@.050.This would keep the lousy Dcr but increase power by nearly 3 cam sizes,

And if I was shopping for a 204*, I'd be shopping for a 244@.050 This cam would pick up the DCr to 7.8@155psi, in a 9.0 teener. And I could keep the 1750 TC and 2.xx gears, if I was so inclined

And finally, if I did install the 262/220 I would be bringing up the compression to take advantage of the low-rpm torque and fuel-efficiency. Yeah that 262/220 can make mileage high into the 20s USg even near or into the 30s with the right final drive ratio.

But hey if I'm wrong I'm sorry, just put me on your ignore list
 
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Maybe I'm preaching to the choir. Maybe I am wrong.
But this cam has a dual personality. It has slow-rpm characteristics like a 262, so below 2000 or so the late closing intake is a problem. Sure if you have a 2400 TC, and never operate down there, it's no big deal when you floor it; cuz then personality #2 takes over. But then it's,(to ME) a total waste of 2400rpm of the powerband, where probably 80% of my driving occurs, and I have a clutch, so in day to day operation,I demand torque from idle on up. If I need power, that is easy; just rev it up and go. But to me this rpm range from Idle to 3000 is extremely important. That's where my engine lives. This above cam totally wastes about 3 sizes of cam at off idle and this decreases to 2 cam sizes by about 1500/1800, and then 1 cam size to about 2200. So yeah, in an automatic with a 2400TC maybe no big deal, I'll concede the point. Just don't stick it in a low-compression teener with a clutch, cuz you'll be sounding like a Mustang.
But I guess if I had a cam like that, new in a box, I could make a quick sale right here on FABO,lol.
But If I was shopping for a 262, I'd be wanting one about 220@.050.This would keep the lousy Dcr but increase power by nearly 3 cam sizes,

And if I was shopping for a 204*, I'd be shopping for a 244@.050 This cam would pick up the DCr to 7.8@155psi, in a 9.0 teener. And I could keep the 1750 TC and 2.xx gears, if I was so inclined

And finally, if I did install the 262/220 I would be bringing up the compression to take advantage of the low-rpm torque and fuel-efficiency. Yeah that 262/220 can make mileage high into the 20s USg even near or into the 30s with the right final drive ratio.

But hey if I'm wrong I'm sorry, just put me on your ignore list
LOL.... nobody putting you on the ignore list. :) You gave some reasons why it won't work, and I like the feedback! Please give an estimate on what E.T. you think it will run?
 
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LOL.... nobody putting you on the ignore list. :) You gave some reasons why it won't work, and I like the feedback! Please give an estimate on what E.T. you think it will run?
Before I get caught with my pants down again;
How what will run?
I have no experience. I only can work off the charts and formular Chrysler worked out in the 60s and seventys. They are very comprehensive, but always assume unlimited SuperStock Type suspension. The charts assume you will be running slicks, SS springs, a traction aider and the correct rear gear.That your car will tu at an advantageous rear weight bias and have proper weight transfer.
We already know a guy can lose.3 to .5 right on the start line, with a feeble starter gear and tire spin. And we can lose another .3 to .5 trapping in second gear at 4400 say. So guessing on an unrun combo is pure speculation.
The charts are organized purely as to power to weight ratios; saying a P/W of such and such will run so many mph. Another chart shows if you ET at such and such, your P/W is such and such. And when the two don't match, then you can figure out what to do about it.

Lets take a 70 Swinger 340 4-speed/3.55s for example. Mine weighed in at 3330 with me in it,in the summer of 71, and I ran it in pure stock. The engine was factory-rated at 275, and factored to 290,IIRC by the NHRA back in the day So we have some numbers. The P/w is 3330/290=11.48 And that should run.....about 104 mph. Mine ran 98and change, I can't recall, mph. This shows I was down at a P/W of 13.1 say, which is 3330/13.1=254 hp, so it was tired,or well off a good tune. This car turned 14.4 so the chart says I was at a P/W of 17.24. I shoulda turned 12.7 according to the P/W selected for the 290hp. And I shoulda turned 13.3 with 254 hp. So, one can see that the street suspension/gearing cost me 14.4 less 13.3=1.1 seconds. And the lazy tune cost me 14.4 less 12.7, less 1.1=0.6seconds.
Next take my tired old 71 Demon 904 hiway geared DD. IIRC it turned 79mph and 15.9 or something. The 79mph says it had a P/W of 23.2. And Ima thinking it scaled about 3450 that day . Well 3450/23.2 is 149 hp.
And the 15.9 is nearly off the chart at a P/W of 22.7. So these two are sortof agreeing; 3450/22.7=152 hp. There could be little to no improvement. in making any changes.
But consider this; that 318 was factory-rated at 230hp! It shoulda had a P/W of 3450/230=15.0. It shoulda gone 93mph with unlimited suspension. And the ET for 15.0 is 14.0.
Now earlier it was shown that the street suspension on the Swinger cost me 1.1 seconds. Adding that to the theoretical ET of 14.0 we get 15.1 seconds. The rest is in the powerloss, in this case costing an additional 15.9 less 15.1= .8 seconds. The power loss can thus be computed using the charts. Then you have to figure out why.
So now if you have a 74 Dart at 3600 raceweight, or was it a Duster? Yeah I think a Duster, so make it less of a tank at 3450 raceweight,say. With a tired 360. But the charts don't account for tired so; Lets call it a 230 hp. 3450/230=a P/W of 15 and that should go 93. And the ET for that is 14.0. then add 1.1 for the chassis and .6 for the tune, and we come up with a best of 15.7.Now you can compensate slower with a tired engine. lets say it's really down at 180 hp, you measured it on a dyno. Then 3450/180=a P/W of 19.17 which is about 85 mph, and that should hit 15.3. To that you can add the 1.1 chassis fudge and come up with 16.3 seconds for an ET. But your chassis could be worse than mine; remember I was running 3.55s. With 2.45s who knows how much slower it might run. I could guess another .5 second. So now we're up to 16.8. But maybe 3450 is not accurate. Maybe your transmission slips. Maybe it's hot that day and your engine just won't pull. Maybe you short shift it so bad the engine never gets on the pipe. Maybe the muffler is severly restricted. Maybe the chassis has a big ol'drag on it sucking it's own horsepower right off the top. Maybe the TC in no good. Maybe the front end is like a parachute.
Just too many variables.
The charts can spit out a nice ideal number with just a race-weight and crankshaft power. That's pretty amazing.
But what if you had a CVT, and were pulling at the peak-rated power, from start to finish? Well that's not in the charts either. Nor is running more than 4 gears or less than 3. In fact in typical street speeds from 100 to 112, the chart always shows the mph to be about 2 mph higher with a manual trans, and in those years it was the A833.
 
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^^^^ alot of typing, alot of formulas, and a lot of math. Before anything can be counted on as achieving/underachieving, a goal or standard to measure against must be set. To say "that cam kills low end", then what would be the proof? Certainly not a piece of paper (your way smarter than that). So what then? A 2.5 60 ft? 2.3 60 ft? What is the expectation for a stock 360 with stock converter and 2.45's in the 60 ft (providing the car hooks)?
 
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^^^^ alot of typing, alot of formulas, and a lot of math. Before anything can be counted on as achieving/underachieving, a goal or standard to measure against must be set. To say "that cam kills low end", then what would be the proof? The V/P.
V/Ps over 160 are soooo nice. Under 100 are very weak.
A 268* in a 7.8Scr teener is about a 94, even tho it might still have 120 psi cylinder pressure.
A true10.5Scr 340 from 1970 might of made a V/P of 144 and had cylinder pressure of 175psi
A 444stroker at 11/1, with a 276/108 cam might make a V/P of 200 and have cylinder pressure of 187. But if you put a 292/108 cam in it, the V/P drops to 165@168psi. That cam just "killed" the bottom end. To get it back she would need a compression boost to 12.8. To look at it another way, that 16* of intake duration cost 1.8 points of compression.

Certainly not a piece of paper (your way smarter than that). So what then? A 2.5 60 ft? 2.3 60 ft? Yes and No. The 60ft is all about putting down as much power as the chassis and tires can handle. If it spins it sux. With 2.45s and a 1750TC there ain't a lot of potential, for TM. So you got to start off with a a big number. If the cam trades away 20 or 30 ftlbs at the stall for about the same at the other end, then the 60 ft will be "killed"
Here's a Hughes curve;
upload_2017-7-28_19-24-24.jpeg


Check out the 170# at 3200. If you hit the start line with a 3200TC and 4.30s, you would be generating 170 x 2.45x4.30=1790#
But if you swapped that 3200 out for a 4000, you'd have the potential to put down 320 x 2.45x4.30=3370#.
So if your chassis and tires were able to deal with that, it would be reflected in the 60ft.
Now extrapolate that torque curve down to an imaginary 1750 rpm. Well you can't cuz of the dip at the tip-in, but Lets say at 1750 you made 80 ft lbs. Now with the 2.45s,you are down to 480# on the line. And if the bigger cam dropped 20 off that, then you are down to a dismal 360# You almost have to wonder how it can idle at all.


What is the expectation for a stock 360 with stock converter and 2.45's in the 60 ft (providing the car hooks)?With slicks,How can it spin? I've never had a challenged combo like that so I can't say.And the answer is not in the charts,lol. But you'll know pretty soon lol.
 
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Well, i don't have slicks on the car, they are normal street tires. But if it launches without spinning, I think it will do just fine. By what standard? Well, knowing it's gears and converter, I would think a 2.1 60 ft would be doing just fine. and if it gets a 2.1, I'll say the cam is doing just fine on the low end.
Just can't set the bar at 1.6 60 ft times like an 11 second car, knowing you got a stock 360 with stock converter and 2.45's in a full weight car, correct? :)
 
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