[ridlenracing]

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.

[stepside454]

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

[ridlenracing]

It is for dirt track, with 2 drivers. I am sure you know what I mean, but anyway, the driver has the steering and brakes, passenger has the gas.

The duration is 224

[stepside454]

I had to make a couple assumptions, Im going to assume per class rules astock manifolds, looks like about 322 HP @ 5000 RPMs & 377 ft lbs @ 3500 RPMs

[Sudden Psycho 31]

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
300 lb ft at @ 5000

ristricted exhaust killed it
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,

31

[ridlenracing]

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.

[tm454]

You say you started with 366hp so add for the cam and figure around 400hp with a decent exhaust system. Wasn't that 366hp with trips?


Tazz


Rat Rods Rule!

[79 camaro 454]

youll have an easy 360hp what you have is a ram air iii with a high lift cam it cant reduce hp.

ram air iii chamber volume is much smaller than on that dyno sheet your cumustion chamber is 72 cc not 86 or whatever is on there..thats a hell of a difference.

[Sudden Psycho 31]

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

31

[stepside454]

Also, dont forget. in 1970, that 366 HP was a gross rating,dont know if that was all that accurate compared to NET rating

[Croz]

peaking in the 6500 rpm band

You are not going to want to rap that old pontiac that high unless you really build it up. This isn't a small block, and it won't rev like one.

[Sudden Psycho 31]

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


31

[Croz]

He did tell us what heads and intake he was using, and we know it isn't going to be making power up that high anyway. I never said it was stock, I was just pointing out that revving this thing up to 6500 is a little pushing it.

[Sudden Psycho 31]

sorry if i was a little fussy, on the last post.

i had just put a screaming 2.5 year old to bed.

i have since recovered

31

[Croz]

Heh, it is no problem. It sounds like you have your hands full.