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can someone give me a estimate on hp!

3K views 15 replies 6 participants last post by  ridlenracing 
#1 · (Edited)
We just built a 400 pontiac for our cruiser car, wish we could use chevy, but this is what we have. A 72 block, not bored, 4 valve relief flat top pistons, #13 heads with the 2.11 intake and 1.81 exhaust. Triple angle valve job, titanium retainers, bronze guides, craine racing springs, crane cam with 465 lift, 112 lobe seperation, ram air 3 intake, not ported or anything fancy, 4 barrel carb. Our compression is not quit 10.5-1, but close. Just a good estamate would be great.
 
#2 ·
I know I know, Chevys are cheaper to build...but seeing a Pontiac motor anymore is way cool. by the way, when you say cruizer car... is that a stock car class...or cruizer,as in a driver ? anyway, need to know cam duration @ .050. Thanks John
 
#5 ·
i ran a couple of scenarios for ya...

with a open exhaust you look to be around the 300-350 hp @ peaking in the 6500 rpm band:D
300 lb ft at @ 5000

ristricted exhaust killed it :mad:
200 horse @ 6000
200 lb ft @ 5500

had a few assumptions... played with those a little ...

thats why i had a range

here is the output... i had to reduce it to fit the posting limits
hope it helps,

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#6 ·
I dont get it. Stock hp from 70 gto ram air 3 was 366-370hp. So why is mine so much lower when I have ram air 3 heads (which are 72cc) with 10.5-1 compression and intake with a 4 barrel carb and a bigger cam. Just confused.
 
#9 ·
on the dyno, i used what info i had.. it should be close if parts are right.
you did not show what type of intake it had, that can make a big difference in high rpm horsepower.
you also did not say the size of the carb.

in the compression math i had @ 73 cc chamber to get you to the compression you stated.

i put in a 800 cfm and a different intake, adjusted the heads

you will like this better, as you can see everything makes a diiference

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#12 ·
Triple angle valve job, titanium retainers, bronze guides, craine racing springs, crane cam with 465 lift, 112 lobe seperation, ram air 3 intake,
you are right... sounds stock to me... LOL

just trying to help, not get it exact.... take a pill

that small stroke big block ought to spin okay.

maybe not 7000, i simply plugged in the info and spit out the results.

no one talked about , intake or head flow, crank bob weight, whether it was balanced, (internal or external), back pressure, ignition.

we can... he didn't


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#16 ·
Just a bit more info to make things easier.

You know about the Ram Air 3 heads all done right. the carb is a rebuilt with some goodies 750cfm quadrajet. Everything is new in the bottom half, arp bolts and better studs throughout.

We ran it to 5,400 rpm and that was all we needed, plus I think we have a bit more if it came down to a shoot out to the finish line.


I want to get more, but still have to stay close to stock, like fricken exhuast manifolds, I should port them and the intake if I could get by with that, na maybe just the exhuast. How about some copper head gaskets or shaving then a couple thousands.


Yeah, 6,000 rpm is to much i think too, thanks for all the good info on here, alot of very helpful guys.
 
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