To Stroke or not to Stroke?

340 550HP, But how???

  • Total voters
    91
-
Going off base here.

Running more octane than an engine requires can have the engine making LESS power. BTDT on the race bikes and other stuff
 
crackedback said:
Going off base here.

Running more octane than an engine requires can have the engine making LESS power. BTDT on the race bikes and other stuff
Click to expand...
hmmm, I wouldn't have thought the exact same recipe could be used in a 340 cu in engine to make 550 hp on 87 octane vs 93.........
 
I just watched a video on Motortrend Ondemand (30 day free trial)
They used these engines in the Amsoil build challenge I believe?
They built a 410 (360 .040 0ver w/4"stroke) and a stock stroke 360 .040 over with the exact same:
Cam - .545 lift hyd.
Intake - Eddy air gap
Heads - Eddy alum. 63cc comb. chamber out of the box
carb - 850 Holly DP.
Comp - 10.1:1
The only difference was the stroke of these engines.
410 made 431 HP, 479 ft lbs torque
360 made 422 HP, 448 ft lbs torque

Just passing on what I saw - I'm planning my 360 build now also, trying to learn all that I can.
 
higher octane allows higher compression ratio. each 1 point increase in compression increases horsepower about 4%
 
Marcohotrod said:
higher octane allows higher compression ratio. each 1 point increase in compression increases horsepower about 4%
Click to expand...
my point exactly...back to the original post - IF I was a potential buyer, build me an 87 octane 550 hp smallblock......
 
Everyone just say 340 is gonna be a high revver. By how much? 500, 600, 1000 rpms ?

Look at that 367 vs 410 the hp was pretty much just a wash at 8 hp difference. Yes the 410 made more torque but then again thats easy enough equalled out by gearing 410 with 3.55 vs 367 with 3.91 will have the same torque to the ground. Thats why I like to say for smaller displacement if your willing to gear it build it if not stroke it or go bigger.

But look at the peak rpms difference not much for 43 cid difference hp 300 rpm and torque 200 rpm I figure there would of been a way bigger gap like twice those rpms.
And if it was 340 vs 410 maybe would only be a couple hundred rpms more not exactly extreme revver.

Thing I like about the smaller engines is the power curve doesn't stop at peak these still usable power above peak hp.

Buy like they said for not much price difference.
So you get away with less stall, gear and gain a few inches of vacuum. If those matter to you.
 
kielbasa said:
so higher octane offers no more horsepower potential in an engine?
Click to expand...

i don't think so.
Hi octane should prevent an engine from firing pre maturely from excessive heat and compression...allowing it to fire from the spark plug at the correct time.
 
RAMM said:
IMO strokers are so overdone--been there done that. I love an efficient engine and that means high HP/CI . There is nothing like a 7000+ rpm engine on the street and that just isn't going to be a stroker. Plus as a builder it will be more of a challenge to pull off a 550HP 340. I'm building a high RPM 371 (3.58") right now that I will get rid of as a good 340 block has come my way. Going to stroke crank to 3.425" (356 cubes) and let it sing. J.Rob
Click to expand...

How do you figure that? My pump 93 434 made peak hp at 6850 and I shift at 7200 on the street or strip. My idea of high rpm's would 8000+.
 
justinp61 said:
How do you figure that? My pump 93 434 made peak hp at 6850 and I shift at 7200 on the street or strip. My idea of high rpm's would 8000+.
Click to expand...
You are in the 1% of stroker guys with heads that can actually make power above 6500 rpm then. Believe me, most strokers don't turn anywhere near 7000 rpm and actually make power there. J.Rob
 
Ported Indys.

I guess I look at things differently than some, if I'm going to build a 340 or a 500 I'm going to put the heads on it that will make power. Unless you're building a low rpm truck engine why build a stroker and choke it to death?
 
justinp61 said:
Ported Indys.

I guess I look at things differently than some, if I'm going to build a 340 or a 500 I'm going to put the heads on it that will make power. Unless you're building a low rpm truck engine why build a stroker and choke it to death?
Click to expand...

wasn't the idea behind strokers to make lo hp and hi torque at lower rpm?
all the 60's strokers were like that to propel heavy cars adequately.I know of 2
360 based 408's with iron heads that only dynode around 375 hp...but they can
boil the hides.
these guys were all square bore / stroke and made hi torque but did not rev hi
400 Buick 4.04 x 3.9
455 Olds 4.125 x 4.25
421 pontiac 4.12 x 4.0
 
ir3333 said:
wasn't the idea behind strokers to make lo hp and hi torque at lower rpm?
all the 60's strokers were like that to propel heavy cars adequately.I know of 2
360 based 408's with iron heads that only dynode around 375 hp...but they can
boil the hides.
these guys were all square bore / stroke and made hi torque but did not rev hi
400 Buick 4.04 x 3.9
455 Olds 4.125 x 4.25
421 pontiac 4.12 x 4.0
Click to expand...

They way I see it is basically cam/heads is the power and displacement is the powerband (rpm) selector.

So when selecting power you want depends what you consider streetable but probably in the .9 to 1.2 hp per cid (408 would be 370 to about 500 hp) street strip 1.2 plus hp per cid.

But most are not gonna want to not go much further than 7000 rpm peak power. So the only way is more cubic inches with appropriate cam/heads. Race guys are probably bring it up to 8500 rpm. But after that unless you can afford complete custom engines some kind of power adder will be needed.
 
I had the same debate a few months ago when I was putting together a 340. I was going to buy a stroker kit but after looking at my ported J Heads my engine builder figured it would not be worth putting out the money for the stroker when I already had most of the parts to do a stock stroke 340.
The other thing that factored into the decision was the engine was going in a light car with deep gears so we figured we could get away with the lower torque engine.
 
ir3333 said:
wasn't the idea behind strokers to make lo hp and hi torque at lower rpm?
all the 60's strokers were like that to propel heavy cars adequately.I know of 2
360 based 408's with iron heads that only dynode around 375 hp...but they can
boil the hides.
these guys were all square bore / stroke and made hi torque but did not rev hi
400 Buick 4.04 x 3.9
455 Olds 4.125 x 4.25
421 pontiac 4.12 x 4.0
Click to expand...

I never figured hot rodders were interested in low HP.
 
justinp61 said:
I never figured hot rodders were interested in low HP.
Click to expand...

with 30,000 members .... interest would probably run from stock slant six to big block stroker and everything in between.
A 375 hp 408 that puts out 475 plus torque makes a very nice street engine.
 
ir3333 said:
with 30,000 members .... interest would probably run from stock slant six to big block stroker and everything in between.
A 375 hp 408 that puts out 475 plus torque makes a very nice street engine.
Click to expand...

I think you missed my point. It's been in several post about high winding short stroke 340's and that strokers were low rpm engines for the most part. My point is that strokers don't have to be limited to low rpm's or be peaky with their power.
 
I shift my little .030 over 340 at 7600 and on accident...last friday touched the limiter at 8200 on my 1-2 shift. Build the screamer!!! I am intrigued by the 3.58 stroke in a 340 block. Stock stroke is great for rpm, so do it too it MRL!!
 
justinp61 said:
I think you missed my point. It's been in several post about high winding short stroke 340's and that strokers were low rpm engines for the most part. My point is that strokers don't have to be limited to low rpm's or be peaky with their power.
Click to expand...

I agree!
 
greymouser7 said:
Mike I have a yellow steel 3.51" forged crank...-trade you for some head work.
Click to expand...
Hmmmmm, idk

Im thinking I need to just build this as a 340 and make everyone a believer that a good designed engine with a short stroke CAN make the power without having to rev it to the Moon. With the right air flow, and the right cam, it can be done. Plus as we all know, the non stroker will NOT make as much low end power, but it may also help it hook up sooner and better and off you go. Not everyone has a race car with race car suspension/tires. Yes its fun to smoke tires, hell my minivan will do that. But to hook and be gone like the wind while the other guy is spinning his life away, thats even more fun.

I love the discussion on this thread, got some people thinking.
 
MRL Performance said:
Hmmmmm, idk

Im thinking I need to just build this as a 340 and make everyone a believer that a good designed engine with a short stroke CAN make the power without having to rev it to the Moon. With the right air flow, and the right cam, it can be done. Plus as we all know, the non stroker will NOT make as much low end power, but it may also help it hook up sooner and better and off you go. Not everyone has a race car with race car suspension/tires. Yes its fun to smoke tires, hell my minivan will do that. But to hook and be gone like the wind while the other guy is spinning his life away, thats even more fun.

I love the discussion on this thread, got some people thinking.
Click to expand...

Trading cubic inches & low idle rpm for High RPM's

900+ late model Holley carb & super victor intake or
tunnel ram
300 cfm heads
1.6 or 1.7 rockers
solid roller lifters/camshaft
crankshaft scraper
milodon or kevko oil pan

i don't think this is much of a challenge for Mr. Liston, just a long list of dilligent (sp?) work. He already built a relatively mild 470hp 340.
maybe a 500hp 318, 600hp 371, stroker poly block, or high winding 400BBM if we are daring to be different/challenging him

at any rate, he could sell a 340 or 360 -the real challenge for him as an elite engine builder is to do it with less trick parts
 
You must log in or register to reply here.
-

Back
Top