440FE = 1hp per cube?

[Joe-JDC]

I have used the .257 x 8 x cfm for lots of years, and it always comes close when you figure the average cfm vs max cfm.   I have seen several dyno tests where an increase of 30cfm from a set of heads, and 30 cfm increase in the intake manifold only gave a 30hp increase, not 60 as most would suspect.  When I started figuring what was wrong, I finally realized that the 30 cfm increase only brought up the average cfm by about 15cfm, thus the 30hp increase, which would hold true if you considered the average vs the maximum flow potential.  JMO, but I have witnessed this many times through the years on dyno testing.  Joe-JDC

[Barry_R]

Easy is in the eye of the beholder - or writer/internet forum poster.  The 1HP/cube level should be a fairly easy target.

I have had several wedge headed engines get beyond that 1.5/cube level - but none of them have been remotely close to anything you'd consider easy.  It takes a pretty well refined package to get there.  Getting the 1HP/cube is a lot easier with street style parts, but still requires good attention - or a frisky cam & intake choice.

The 2 HP per cfm is as noted - a guidance number at best.  As JDC noted - it can be pretty close or far off depending on the combination wrapped around those heads.  On the flow benches around here a bone stock Edelbrock head will blow around 252-254 at .600 lift.  Theoretically it should thus support up to +/- 500HP.  We struggle to hit that number with street oriented 445 cid combinations and usually come in 450-475ish at best.  Slipping one of my castings into the combination will gain about 30-40 cfm and gets us over the 500 bubble pretty cleanly, but still short of the 2 per.  Take that same head and stick it onto a 482 and the similar behaving combo will go past 600HP regularly - exceeding that same rule of thumb.  That's 100 horsepower with the exact same heads - combination, combination, combination...

[NIsaacs]

It's not that tough to get 1 horsepower per cube these days.  It is much more difficult to get 2 HP per intake cfm; you need a really good cam and intake combination to get there. 

x2.  The hp per cube goal is fairly easy.  The hp per cfm is not.  In addition to what Jay said, any engine that gets 2 hp per cfm is likely to be a high compression deal.  Possible on high octane pump gas?  Yeah, possible, but not at all easy in my opinion.  Getting 2 hp per cfm requires everything to be optimized and sacrifices to be made, such as driveability.   We are of course talking about naturally aspirated engines. 

JMO,

paulie

 The old combo had stock D2 heads, performer intake, 280h comp cam, and 750 edelbrock carb. I don't have the exact compression ratio, just guessing about 10.5.

Nick
 

This was the combo for the dyno sheet. This is with the c-6 and 3k stahl, open headers, 1.750 primaries.

Nick

[NIsaacs]

So, with the same short block as the above dyno sheet, will this engine make the 1hp per cube? I don't have the deck height, but the pistons are the Speed Pro 4.190 bore with a 10.30 cc dish with 4 valve reliefs, 4.40 bore, .038 compressed gasket and 72 cc Edelbrock heads. Complete Ed. top end kit. Heads, rpm manifold, rpm cam, 850 Ed. carb, Pertronics dist. set at 21 initial, 37 total, 1.750 primary piped open headers.

There is a guy that pulls in the Super Stock class with a 393 de-stroked 400 Chevy that pulls with the big dogs (500+ engines) He says the de-stroked rod/piston combo is better than a stroked 350. I love to watch his truck scream down the track. He is currently building a 496 big block Chevy that he says will be 2.1 hp per cube. If his little 393 is an indicator of him and his engine builder, this new engine will trash the Super Stock class, if the chassis will handle that kind of power.

Nick

[plovett]

OK, we agree, sorry, you are still as cool as I thought you were before 

Thanks man.........  I think.   

paulie

[plovett]

I have used the .257 x 8 x cfm for lots of years, and it always comes close when you figure the average cfm vs max cfm.   I have seen several dyno tests where an increase of 30cfm from a set of heads, and 30 cfm increase in the intake manifold only gave a 30hp increase, not 60 as most would suspect.  When I started figuring what was wrong, I finally realized that the 30 cfm increase only brought up the average cfm by about 15cfm, thus the 30hp increase, which would hold true if you considered the average vs the maximum flow potential.  JMO, but I have witnessed this many times through the years on dyno testing.  Joe-JDC

I wasn't trying to discount average flow, Joe.  I do believe the average or I would rather say, the sum, is what counts in the end.  How much power an engine makes is essentially the sum of the flow at all points when the intake valve is open.   Your point about peak flow and it's affects, vs. average flow, are well taken.

JMO,

paulie

[plovett]

The old combo had stock D2 heads, performer intake, 280h comp cam, and 750 edelbrock carb. I don't have the exact compression ratio, just guessing about 10.5.

Nick
 

This was the combo for the dyno sheet. This is with the c-6 and 3k stahl, open headers, 1.750 primaries.

Nick
[/quote]

I think 243 RWHP sounds reasonable with D2 heads and a Performer intake, especially with a C6 and a 3000 rpm stall converter.  You might have been making 340 flywheel hp at that point.  Add Edelbrock heads, an RPM intake, and a bigger Holley carb and I could see gaining  50-60 flywheel hp.

JMO,

paulie

[plovett]

So, with the same short block as the above dyno sheet, will this engine make the 1hp per cube? I don't have the deck height, but the pistons are the Speed Pro 4.190 bore with a 10.30 cc dish with 4 valve reliefs, 4.40 bore, .038 compressed gasket and 72 cc Edelbrock heads. Complete Ed. top end kit. Heads, rpm manifold, rpm cam, 850 Ed. carb, Pertronics dist. set at 21 initial, 37 total, 1.750 primary piped open headers.

There is a guy that pulls in the Super Stock class with a 393 de-stroked 400 Chevy that pulls with the big dogs (500+ engines) He says the de-stroked rod/piston combo is better than a stroked 350. I love to watch his truck scream down the track. He is currently building a 496 big block Chevy that he says will be 2.1 hp per cube. If his little 393 is an indicator of him and his engine builder, this new engine will trash the Super Stock class, if the chassis will handle that kind of power.

Nick

It could make 1 hp per cube with your short block.  You may need more cam, or a different cam to push you over the 1 hp per cube mark.  The 280H cam is a fine cam but it's not cutting edge and it's not overly big for a 440 inch engine.  I'd go bigger if you have enough gearing and compression to support it.  The Edelbrock RPM cam is a bit bigger, but not I what I'd pick.  Go with a solid flat tappet cam in the 242-248 degree @ 0.050" range with net lift in the 0.560-0.590" range and you're there, in my opinion.

Also, I think you should verify the volume of the combustion chambers in your Edelbrock heads.  I also have the "72 cc" versions, but mine have 79 cc chambers.  Mine are very early heads and that is likely why.  Yours are probably close, but it's so easy to check that you might as well.  On an old engine build a long time ago I had TRW 2245 pistons in my 428 and I thought I had around 10:1 compression.  I actually had around 9.3:1  compression.  A pretty big difference.   I think you probably want the true compression ratio to be in the 10.0:1 to 10.5:1 range

paulie

edit:  added solid flat tappet recommendation.

[plovett]

There is a guy that pulls in the Super Stock class with a 393 de-stroked 400 Chevy that pulls with the big dogs (500+ engines) He says the de-stroked rod/piston combo is better than a stroked 350. I love to watch his truck scream down the track. He is currently building a 496 big block Chevy that he says will be 2.1 hp per cube. If his little 393 is an indicator of him and his engine builder, this new engine will trash the Super Stock class, if the chassis will handle that kind of power.

Nick

I would think that a big bore short stroke SBC would out-power and out-pull a small bore long stroke SBC any day. It'd have to be geared correctly and run at whatever rpm the induction can support, but it WOULD do it. 

JMO,

paulie

[NIsaacs]

Bare with me for a minute with all the info I am learning. But, if the rpm hydraulic cam is 236 @50 and .572 lift, is that not about the same as a solid 242-248 @ 50 and .560-.590 lift, when you factor in the valve lash? My English teacher always told me not to start a sentence with "but" but some times ya gotta

Nick

[My427stang]

Bare with me for a minute with all the info I am learning. But, if the rpm hydraulic cam is 236 @50 and .572 lift, is that not about the same as a solid 242-248 @ 50 and .560-.590 lift, when you factor in the valve lash? My English teacher always told me not to start a sentence with "but" but some times ya gotta

Nick

Short answer is no, but your thought process is valid. You are correct that when you subtract lash from the solid cam you will lose lift and duration at the valve.  However, it is typically not that much of a duration change and more importantly, the hydraulic lifters will eventually get more difficult to control at higher rpm, taking power away that the solid cam will provide.

[plovett]

Bare with me for a minute with all the info I am learning. But, if the rpm hydraulic cam is 236 @50 and .572 lift, is that not about the same as a solid 242-248 @ 50 and .560-.590 lift, when you factor in the valve lash? My English teacher always told me not to start a sentence with "but" but some times ya gotta

Nick

Yeah, you're right.   A 236 duration hydraulic is about the same equivalent duration as the solid range I mentioned.  A good rule of thumb is to add 8-10 degrees for an equivalent solid cam.

I think a solid would make more overall power though.  That Edelbrock RPM cam can work.   I don't think most engine builders would pick it compared to something else.  It's an old school design with pretty slow ramps and I've read it's not that great.  Barry's about to tell me cams can't read and he's right of course.      I've never run the RPM cam. 

Do you have adjustable rocker arms?

paulie

[My427stang]

Nick, what RPM range do you run during the event?  I think the most important thing is to not look at the HP goal alone but be sure the engine matches the track and truck not the dyno...

There are a lot of moving parts on this post that need to be addressed, but I think where you want it to make power is the most important

[Joe-JDC]

I have been accumulating Holley Street Dominator intake manifolds, and Edelbrock Streetmaster intakes to try to prove a theory about increased airflow and the correlation to hp increases.  I have 3 of each, and I plan to port them so that there is a 30cfm difference between each of them, and then port a set of either Edelbrock RPM heads, and BBM heads so that they have a 30cfm difference and then do extensive dyno tests of the different combinations along with a RPM intake, and Victor, BT8V, TW, etc..  I had hoped to have a couple of shortblocks available for this, also, one +.030 CJ, and a 4.390" x 4.250 stroke BBM block.  I already have all the parts here, it is just coming up with the time to get everything ported, machined, and assembled.  Should be an interesting test, with some of the heads flowing over 350cfm.  I have a set of Survival heads that can be thrown in the mix, also.  Just need a dyno that is available for that much testing, and is from a reputable shop.  I have a couple available locally, but unless there is a known test comparison, it will always be suspect.  One has had a EMC engine to compare with, so I trust it.  We shall see.  Would travel to any shop on the forum if this was a possibility for them to verify.  Joe-JDC.

[NIsaacs]

Nick, what RPM range do you run during the event?  I think the most important thing is to not look at the HP goal alone but be sure the engine matches the track and truck not the dyno...

There are a lot of moving parts on this post that need to be addressed, but I think where you want it to make power is the most important

I agree, I have had numerous conversations about a dyno test v/s real world testing on the diesel forum that I frequent. That a 10 second dyno run in a controlled environment, is not the same as towing up a 6% grade for 5 miles in 100 degree heat, foot to the floor, and towing 26k GCW.

I run 3k to wot, about 5800 rpm max, that's all it will pull. I have no problem launching the sled, so low end power is not an issue.

I am running the oem, non-adjustable rockers. I think because the rpm cam is old school with slow ramps, valve train control is not a big of issue as the quick ones. Power wise I am sure there are some way better, but the way it runs and revs, I am liking it https://www.youtube.com/watch?v=Mg8CWzqq2kw

Nick