340 stroker

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ir3333

ir3333

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who have built a 340 / 372 stroker
Scat offer cast and forged crank rotating assemblies.
how do you like this combination?
 
Never ran that combo, but if I'm going to buy a rotating assembly I'm going with at least a 4" stroke. Not much more in a 372 than a .030" over 360.
 
I built one for my Dart and love it. I used a .030 over 340 block, which would be a .070 over 360. It has loads of power down low and revs up real good. Yes basically you have a .070 over 360 but the stroke to rod ratio on a 360 is matched real good. Myself I don't like the big stroke small blocks with the short piston skirts and high wrist pin location. That's just me.
 
..this combination was not easy to come by when the 4" kits were everywhere.
..but now Scat offer about five 340 / 372 combinations staring around $1000 w hyper
pistons or $1200 balanced.
thinking 372 might be a better "all round" engine than the 4" torque monsters.
your thoughts?
 
look at the 383 chevy vs 383 mopar dyno test, the chevy is 3.75" stroke and the mopar at 3.38" made equal horsepower and more low end torque. (both with- equal cams, equal compression ratio, intakes, headers, same carb. years ago car craft tested the 440 mopar, 454 chevy, 460 ford, 455 buick/olds/pontiac, equal-cams etc. and the 440 with the shortest stroke made the most torque and tied the bigger engines for hosepower. big strokers are overrated, go for the 372, I am happy with my +.020" X 3.48" 360 cu. in. 340 street car running 11's with J heads and pump gas
 
you can buy a 3.58 stroke 340 main crank....use stock rods...and KB 107 with a 4.07 bore if you want a budget one
 
what's the comp height on the kb 107's?
i'm .135 taller w / 3.58 stroke...correct?

never mind..just looked it up..tx
 
Depending on the cylinder head used and the camshaft a 416/418 will have loads of torque but will be all done by 5000rpm.
Will probably break the tires loose at will, but run out of steam soon after. Totally different character than a "short-stroke" 340 or the mentioned 372 with its 3.58" stroke.
Depending on what you're after this might fit the bill... or not.
 
stixx said:
Depending on the cylinder head used and the camshaft a 416/418 will have loads of torque but will be all done by 5000rpm.
Will probably break the tires loose at will, but run out of steam soon after. Totally different character than a "short-stroke" 340 or the mentioned 372 with its 3.58" stroke.
Depending on what you're after this might fit the bill... or not.
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Thank you!
 
stixx said:
Depending on the cylinder head used and the camshaft a 416/418 will have loads of torque but will be all done by 5000rpm.
Will probably break the tires loose at will, but run out of steam soon after. Totally different character than a "short-stroke" 340 or the mentioned 372 with its 3.58" stroke.
Depending on what you're after this might fit the bill... or not.
Click to expand...


Not true whatsoever. Never had a 4 inch stroke anything that was done at 5k. Not sure who told you that. Get the proper sized cam for that size motor, and even with ported eddie heads it will pull strongly to 6500 rpm without working up a sweat. You can run out of steam up top with too much gear and a small head, but anything ported eddie or better with correct camshaft will pull strongly to 6500.
I had a 4 inch with W5 heads that i crossed the stripe at 7400-7500 every single pass on it. Indy heads would be similar
The mistake most make is way too small on the camshaft side. The extra stroke eats up lots of duration
 
stixx said:
Depending on the cylinder head used and the camshaft a 416/418 will have loads of torque but will be all done by 5000rpm.
Will probably break the tires loose at will, but run out of steam soon after. Totally different character than a "short-stroke" 340 or the mentioned 372 with its 3.58" stroke.
Depending on what you're after this might fit the bill... or not.
Click to expand...

This should be common knowledge, you put small heads and cam on a stroker and you have a low rpm torque monster.

Building a stroker is just like building any other engine, you need the right combination of parts to get the most out of it.

You've built small block strokers? What were they?
 
B3422w5 said:
Never had a 4 inch stroke anything that was done at 5k
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justinp61 said:
You've built small block strokers? What were they?
Click to expand...

Err, I was strictly referring to a standard stroker build, using unported J heads. Which is what a lot of people do since they don't have the coin to even use Edelbrock heads or something iron ported properly. I do know what you can do with money... though admittedly I have never built a stroker :).
 
stixx said:
Err, I was strictly referring to a standard stroker build, using unported J heads. Which is what a lot of people do since they don't have the coin to even use Edelbrock heads or something iron ported properly. I do know what you can do with money... though admittedly I have never built a stroker :).
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I agree. Big waste of money building a stroker and putting dinky heads on it that wont support the xtra inches. Not sure why anybody would do that, frankly.
 
B3422w5 said:
I agree. Big waste of money building a stroker and putting dinky heads on it that wont support the xtra inches. Not sure why anybody would do that, frankly.
Click to expand...
Many people do.

I know my W2 head 408 revs way quicker and wants to go much higher in rpm than another 408 I know with Edelbrock heads and a larger cam. Heads play a huge role in RPM capability.
 
cpearce said:
Many people do.

I know my W2 head 408 revs way quicker and wants to go much higher in rpm than another 408 I know with Edelbrock heads and a larger cam. Heads play a huge role in RPM capability.
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W2 or Eddie heads with porting are one thing. Putting stock J heads on a 408/416 is another thing entirely

Sure a W2 will act differently. A W2 is a race head. An eddie is a factory replacement head. Big difference in potential
 
It seems a lot of people here have the misconception that engines with 4" and bigger cranks won't or don't like to rev or that they are slow to rev.

My 408 was very quick, it was fastest shifting at 6400 because it was running out of head flow, it had the cam and everything else was there it was just running out of air.

The 434 currently in the car has a 4.125" stroke and it revs every bit as quick as the 408 did. This engine made peak power at 6750. I don't have the chassis sorted out yet to be able to find what it likes best, but will hazard to guess it'll be over 7000 when everything is fine tuned.
 
justinp61 said:
It seems a lot of people here have the misconception that engines with 4" and bigger cranks won't or don't like to rev or that they are slow to rev.

My 408 was very quick, it was fastest shifting at 6400 because it was running out of head flow, it had the cam and everything else was there it was just running out of air.

The 434 currently in the car has a 4.125" stroke and it revs every bit as quick as the 408 did. This engine made peak power at 6750. I don't have the chassis sorted out yet to be able to find what it likes best, but will hazard to guess it'll be over 7000 when everything is fine tuned.
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Agreed, they will rpm with heads that support the cubic inches. The fact of the matter is many people are building these strokers with production heads in some form or another. These engines go soft over 5500rpm. Then their lack of RPM capability is not a misconception.
What heads are you running? Indy or W5? I suspect something quite large to support the 4.125" stroke.
 
The heads on the 408 flowed in the mid 290's on Curtis Boggs bench, the cam was 260/264 at .050".


The 434 has Indy 360-1's and an Indy intake.

I understand that a lot of people are building these engines using factory castings, but they need to understand what they are going to have. In a lot of cases it's not what they expect. Nothing wrong if that's what you want or can afford, I'd do it too if needed, only I wouldn't complain because my engine fell on it's face at 5000 rpm's. I'd throw a set of 3.23 gears under it and have fun.
 
justinp61 said:
The heads on the 408 flowed in the mid 290's on Curtis Boggs bench, the cam was 260/264 at .050".


The 434 has Indy 360-1's and an Indy intake.

I understand that a lot of people are building these engines using factory castings, but they need to understand what they are going to have. In a lot of cases it's not what they expect. Nothing wrong if that's what you want or can afford, I'd do it too if needed, only I wouldn't complain because my engine fell on it's face at 5000 rpm's. I'd throw a set of 3.23 gears under it and have fun.
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Agree 100%
 
Getting back to the 340 block and the 360 crank combo, this old tyme poor mans stroker is an interesting combo that I like. While true it is likened to only a highly overbore 360. It is the big bore that makes it attractive IMO.

(I’d like to even see such a combo of the stroke and a bigger bore.)

It will run very similar to a 360 but with a little more top end pop since the bigger bore will hand out such performance. Street or strip performance should be really good with it. If money is tight, a set or prepped Edelbrock heads will do the job as opposed to the need of a bigger more capable head being fully ported for maximum efforts and returns. The Edelbrock heads are fine for a street engine without porting. Though size limited in there stock configuration, they should be OK for a street runner @ 373 cubes.
 
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