500hp & 600hp Bench Racing thread

[273]

Just curious

What would your 500 hp combo’s be for a 0.060” overbored 340 block so 4.10” with each one of these strokes 2.96”, 3.58” & 4”

and what would your 600 hp combo be for a 4.375” bore 400/440 block with these strokes 3.38”, 3.75” & 4.25” ?

shooting for pretty close to those hp goals for each.

 

[Rat Bastid]

Any LA a engine is **** for a 2.96 stroke. The decks are far too tall. The pin height will be over 2 inches. HORRIBLE.

3.58 stroke is 360 so I’d be setting it up to shift at 7000-7200. It would take a fully ported head and a solid lifter cam that’s at least 265 @ .050 to do that. Minimum 11.25:1.

For the 4 inch stroke I’d drop the RPM back to 6500, I’d probably be 272 @ .050 and I’d bet it would be on a 103 LSA.

 

[rumblefish360]

My 2 cents s in the small blocks.

3.58 stroke is 360 so I’d be setting it up to shift at 7000-7200. It would take a fully ported head and a solid lifter cam that’s at least 265 @ .050 to do that. Minimum 11.25:1.

I’d follow this as well. A lot depends on the cylinder head on hand which can change the camshaft selection. Currently the 340 I’m working with is on a 108 LSA, well ported aluminum heads and a 2.08/16.0 valve set up. It’s not a 500 hp build, though I expect a good street machine engine.

For the 4 inch stroke I’d drop the RPM back to 6500, I’d probably be 272 @ .050 and I’d bet it would be on a 103 LSA.

I’m doing this now (parts collection actually, I have most of it) the cam I have for this is a Ultradyne solid FT @ 272@050 intake. On a 102. It’s a NF lobe. I’m sure it’ll sore past 500 hp. We will see what the dyno says.

 

[Rat Bastid]

My 2 cents s in the small blocks.


I’d follow this as well. A lot depends on the cylinder head on hand which can change the camshaft selection. Currently the 340 I’m working with is on a 108 LSA, well ported aluminum heads and a 2.08/16.0 valve set up. It’s not a 500 hp build, though I expect a good street machine engine.

I’m doing this now (parts collection actually, I have most of it) the cam I have for this is a Ultradyne solid FT @ 272@050 intake. On a 102. It’s a NF lobe. I’m sure it’ll sore past 500 hp. We will see what the dyno says.

Can’t wait for the dyno results

 

[rumblefish360]

Can’t wait for the dyno results

Thanks, I’ll can’t wait for the rest of the parts!
Actually, I just wanna finish up the bull **** in front of me so I can get to my flippin retirement toys!!!
DANG NABBIT!!!!!!

 

[pittsburghracer]

Just curious

What would your 500 hp combo’s be for a 0.060” overbored 340 block so 4.10” with each one of these strokes 2.96”, 3.58” & 4”

and what would your 600 hp combo be for a 4.375” bore 400/440 block with these strokes 3.38”, 3.75” & 4.25” ?

shooting for pretty close to those hp goals for each.

I’m not big on quoting Hp numbers because I don’t trust dyno numbers. For the 4.100 bore 340 and 4 inch crank I feel it’s over 500 horsepower running 5.98 in the 1/8 and 9.42 in the 1/4.

according to Direct Connection my .030 over 440 with a stock crank ran 9.82 back in the 1980’s and should be close to 600 Hp. with 906 heads, stock rods, TRW pistons, .750 lift roller cam, tunnel ram with two 750 Holleys. Just think what todays heads would run on that combo.

 

[PRH]

This seems like a trick question.......

According to the OP, cubes don’t make any difference in power.

So, you just come up with a combo of parts, and it’ll make the same power........ regardless of engine displacement.
Easy peasy.

 

[273]

This seems like a trick question.......

Not really just wanted see what people would do different.

According to the OP, cubes don’t make any difference in power.

When I look at most builds making similar power, I find the parts are similar across cid and brands and when you factor in the stall and gearing most the differences disappear.

So, you just come up with a combo of parts, and it’ll make the same power........ regardless of engine displacement.
Easy peasy.

Not saying that, I would think it's combo dependent, obviously generic top parts may favor different bottom ends is it always 100% the larger one? I don't see a 400 need 50-60 more degrees of cam and 50-100 cfm head flow etc.. to make 600 hp compared to a 500.

 

[pittsburghracer]

I’m sure we all know there are ways to compensate for poor flowing heads.

 

[PRH]

I realize I’m probably just “doing it wrong”, but when I build two engines using extremely similar top end components and camshafts....... miraculously........ the one with the bigger displacement ends up making more power.
I realize that doesn’t have the credibility of formulas & theories gleaned off the ‘net........ just real world builds and results.

 

[273]

I realize I’m probably just “doing it wrong”, but when I build two engines using extremely similar top end components and camshafts....... miraculously........ the one with the bigger displacement ends up making more power.
I realize that doesn’t have the credibility of formulas & theories gleaned off the ‘net........ just real world builds and results.

Fair enough but then what's holding the smaller engine from spin up to match hp?
What differences need to be done so it can?

 

[PRH]

As soon as you change something to compensate for the displacement, it’s not the “same” anymore.

The tests I’m referring to used the “same” top end components, and the larger displacement engines produced more tq/hp with those same components.
Sometimes, quite a bit more.

But I know....... those are just pesky real world results.

That’s all the time I’m going to spend on these “black hole of time” threads.

 

[273]

just real world builds and results.

Yes I don't have a dyno and not discounting your professional experience but I'm not basing my thoughts out of thin air either and not saying it's the same as your experience but I got make do with info available to me, but I going on 40 years of poring over and comparing every engine build I've seen. Why I'm trying to understand but I need a theory to base it on not cause "we say so", There must be a theory what's holding the smaller displacement back since we know the top end is capable of the hp?

 

[33IMP]

Fair enough but then what's holding the smaller engine from spin up to match hp?
What differences need to be done so it can?

Nothing. What's holding up the bigger engine to spin as fast as the smaller engine, and make more power?
Bottom line, valve train will determine how fast it can spin, and lower end parts will determine if it lives at that rpm.

 

[PRH]

Here’s a very simple explanation of why cubes work.......but you’ll have to connect the dots.

If I tell you a head flows 300cfm....... is that enough information to be useful?

 

[Phreakish]

Yes I don't have a dyno and not discounting your professional experience but I'm not basing my thoughts out of thin air either and not saying it's the same as your experience but I got make do with info available to me, but I going on 40 years of poring over and comparing every engine build I've seen. Why I'm trying to understand but I need a theory to base it on not cause "we say so", There must be a theory what's holding the smaller displacement back since we know the top end is capable of the hp?

More CID by definition means more stroke or more bore. BOTH of those equate to greater generation of forces. Overcoming that with RPM requires a different cam for the little guy.

Years and years and years of testing more less show that part-swapping really only 'tilts' the HP curve (top end goes up, bottom end goes down, etc). There needs to be a change in engine efficiency (cylinder head flow and QUALITY of flow, ring packages, rod ratio, etc) to shift the curve straight up. But if you shift it, the same thing will happen to the bigger motor with the same changes. Changing most of these things also tends to cost more than swapping a cam or headers.

So, in a nutshell, generating power with RPM means giving up low-end or fabricating bespoke parts. In a racecar, the rpm trade can be worth it since the car will live full-time above 5k. But the same changes to induction can be made to the bigger motor to also spin faster... a die grinder is cheap and quickly takes all the slow out of the ports - just don't grind the fast out of them.

 

[273]

Here’s a very simple explanation of why cubes work.......but you’ll have to connect the dots.

If I tell you a head flows 300cfm....... is that enough information to be useful?

If I say I got a 340 duster and a 440 duster is that enough info to know which one makes more horsepower ?

 

[PRH]

In typical fashion, you didn’t answer the question.

I’m out

Why I'm trying to understand but I need a theory to base it on not cause "we say so", There must be a theory what's holding the smaller displacement back since we know the top end is capable of the hp?

I’m trying to help you understand the principles at work....... but you really don’t want to hear them.

 

[273]

More CID by definition means more stroke or more bore. BOTH of those equate to greater generation of forces. Overcoming that with RPM requires a different cam for the little guy.

Yes but by large amounts of just fine tuning opening and closing valve events and lsa ?

I would expect port shape needs to be slightly different also along with intake and exhaust lengths etc.. And stall gearing etc... All this stuff is inter connected so same would be relative term, cause if everything is exact same then it's gonna be mire optimal for one.

 

[273]

In typical fashion, you didn’t answer the question.

I’m out



I’m trying to help you understand the principles at work....... but you really don’t want to hear them.

No it doesn't that was my point

 

[33IMP]

If I say I got a 340 duster and a 440 duster is that enough info to know which one makes more horsepower ?

If I say I have an engine with ported aluminum heads, 11 to 1 compression, 750 holley, edelbrock intake, solid cam, 6500 rpm, 1 7/8 headers, and I asked you to guess how much power I have, what is your first question?

 

[PRH]

No it doesn't that was my point

Okay, what about if I add it’s an Ede Rpm BBM head, 2.14” Intake valve at .700” lift....... is that enough info?

 

[Phreakish]

Yes but by large amounts of just fine tuning opening and closing valve events and lsa ?

I would expect port shape needs to be slightly different also along with intake and exhaust lengths etc.. And stall gearing etc... All this stuff is inter connected so same would be relative term, cause if everything is exact same then it's gonna be mire optimal for one.

If you can afford to fine tune those types of things on a 273, they'll pay bigger dividends on a 408. This is exactly what I mean when I say 'all things equal' - it means equal effort.

This is why your premise of 'the same parts' isn't useful in any case. What works for one is rarely the right choice for the other. The same level of effort though will reap greater power with a larger displacement.

Also, most hot rod parts are going to favor more cubes anyway. Building a high RPM screamer takes a more bespoke approach. It's not impossible to win with RPM, it's just not the type of program which can be described in a forum post.

 

[273]

If I say I have an engine with ported aluminum heads, 11 to 1 compression, 750 holley, edelbrock intake, solid cam, 6500 rpm, 1 7/8 headers, and I asked you to guess how much power I have, what is your first question?

flow numbers and better cam specs, my guess would at least 550 hp

 

[273]

Okay, what about if I add it’s an Ede Rpm BBM head, 2.14” Intake valve at .700” lift....... is that enough info?

No, it would tell us probably the max hp capability were dealing with.