Power

[Grip64]

Hi fella's
Looking for some input please....

I have been running a 440 stroked to 500'', large valve 915 heads, cam dur@50 247/252 in at 110.
40'' quench, street dominator intake, 750 dp, HP manifolds.
This made 450hp on the dyno, using 99 octane fuel, with 10.4.1 compression.

My question is, using the same combination but going to 12.1 compression and running c12 gas, what sort of power increase would i be looking at and would it be worth the hassle of going up 1.6 points

Thanks in advance for your reply's   

[Ghoste]

I'd do it for a drag car but for me in a street driven car, the expense and hassle of keeping the race fuel in it all the time wouldn't be worth it.

[BSB67]

Hi fella's
Looking for some input please....

I have been running a 440 stroked to 500'', large valve 915 heads, cam dur@50 247/252 in at 110.
40'' quench, street dominator intake, 750 dp, HP manifolds.
This made 450hp on the dyno, using 99 octane fuel, with 10.4.1 compression.

My question is, using the same combination but going to 12.1 compression and running c12 gas, what sort of power increase would i be looking at and would it be worth the hassle of going up 1.6 points

Thanks in advance for your reply's    

With exhaust manifolds, it might pick-up considerable power with a different, smaller cam

On reconsideration, if that is RWHP, disregard my comment above.

More sqeeze will help.  I cannot say how much, and only you can answer if it is worth it .  Have you had it to the track?  what did it run?

[Challenger340]

"ENGINE" Dyno or "Chassis" Dyno ?

450hp at the "wheels" if we assume Chassis Dyno, would mean roughly 20% more at the Flywheel or approx 555 ENGINE hp ?

You will only gain very marginally with the CR increase(if at all), because, UNLESS your big valve 915's are serverely ported, you are about cfm'd out.
All the CR increase will do, is raise TORQUE, and some minor hp, EARLIER in the powerband.

[Grip64]

Yes that's 450hp on the engine dyno.

Best time is 12.40's@110 in 3900lbs car.

The 12to1 combo i'm thinking of would use smaller chamber heads to give the higher compression, heavely ported 915's flowing 280, and the same cam thats in the present combo, which is one of Dwayne's 247/252 114 lsa in at 110, with 550 lift.

I would be using c12 and High octane pump gas mix, 50/50 for the track.

[FLG]

Why not throw some better flowing aluminum heads on her?

[BSB67]

Yes that's 450hp on the engine dyno.

Best time is 12.40's@110 in 3900lbs car.

The 12to1 combo i'm thinking of would use smaller chamber heads to give the higher compression, heavely ported 915's flowing 280, and the same cam thats in the present combo, which is one of Dwayne's 247/252 114 lsa in at 110, with 550 lift.

I would be using c12 and High octane pump gas mix, 50/50 for the track.

Hmmmm.  Something does not seem quite right.   What was the DA when you raced,  or elevation and weather.  What kind of convertor? do you know your fuel pressure in the traps? and how old in your exhaust system and mufflers?  Was it Dwaynes dyno?  What is you cylinder cranking pressure?

[Chryco Psycho]

a similar build that I did made 400 RWHP on a Mustang dyno
the difference is TTi headers & a 950 CFM Carb
Carb is way too small , you are running a 2 bbl !!
double the CI is 1000 cfm , we used a Proform 950 race series carb on the one we built
& the manifolds are restrictive , the cam should  be a 112 cl if used with manifolds  not 110

[1Bad70Charger]

"ENGINE" Dyno or "Chassis" Dyno ?

450hp at the "wheels" if we assume Chassis Dyno, would mean roughly 20% more at the Flywheel or approx 555 ENGINE hp ?

You will only gain very marginally with the CR increase(if at all), because, UNLESS your big valve 915's are serverely ported, you are about cfm'd out.
All the CR increase will do, is raise TORQUE, and some minor hp, EARLIER in the powerband.

This man KNOWS what he is talking about! 

[Cooter]

500 C.I. and "HP" manifolds???


I'd be lookin' for a set of headers before opening up the engine....

[Mike DC]

 
I agree.  Needs bigger cylinder heads and tube headers rather than iron manifolds. 

[BSB67]

 
I agree.  Needs bigger cylinder heads and tube headers rather than iron manifolds.  

There is no reason that it should not be making 500 to 525 hp IMO.  Why throw money at it instead of spending some time to make sure everything is as it should be.  I do think a larger carb would help.

I'm sure that he is asking about CR as the A12 FAST guys are probably at 625 to 650 hp using a bunch of squeeze.

[acelondon]

I'd say 900+CFM carb, headers, maybe better heads. No reason an engine that size wont make 500hp. I was just reading an article about a guy pushing 700 from a 500" Dodge. My buddy's 318 is pushing 425HP.

[redmist]

My .030 over 440 made 500 HP and 542 ft lbs on the engine dyno. I would say you have something not matched for sure!!

[elacruze]

The cam seems too small to me. My 505" has a 258* .572" lift @112 LSA and 107* intake centerline, and makes good torque and drivability from idle to 2000.