schoenchen144

Ok all engine builders and gurus. I was doing some digging and tinkering on my 454 in my car, and as it turns out, this big bad high compression engine is not as bad as it seems. So here is what I know. Oval port heads, 781's @ 116-119 cc chambers, KB-227-70 pistons(427 pistons actually) they have a .250 dome, .070 over bored. Comp cams XE268 cam, Carter 750 carb on a dual plane intake with headers and 3 inch exhaust. Im figuring the compression is not a wild 12:1 ratio but a much tamer @ 9.5-9.7:1 ratio. SOOO....my question is what would your guess on the horsepower be. Roughly??
Anyone have any ideas???

cutlassefi

Ok first of all you don't have a 454, you have a 440, 396/427 crank in a .070 over 454 block.
With that cam and combination my guess would be approx 400-425hp. That cam and carb are holding you back.

rustyroger

I give in, how can you tell he doesn't have a 454 crank?.


Roger.

Octania

You gotta remember that brand C horses are smaller, so there will be a higher number for the same power level. Maybe 450-504.

It's all guesswork anyhow.

cutlassefi

Simple, the compression distance on that piston is 1.765. Add that to 6.135 (rod length) and approx. 1.880 (half the stroke) and you get 9.78. Standard deck height on a BBC is 9.800. Easy math.

cutlassefi

Not sure what you mean here.

Seff

I'd venture the guess that Octania is alluding to Chevy engines apparently having more horses on paper for the same power "feelling" (assuming this is measured by the almighty Butt-Dyno™) as a more torquey engine with less horsepower.

rustyroger

I didn't know the piston height, thank you.
Assuming he has stock length rods of course...


Roger.

Octania

Right
Magically bigger HP numbers breathing thru them tiny nostrils. OK, sure. No one has ever fudged dyno numbers. What temperature- what?

Seff

I wasn't going to say that.

cutlassefi

He gave the piston number, I just looked it up.
And I don't know anyone that makes a BBC rod that's shorter than stock and a longer than stock would poke the piston out of the deck. Again easy math.

rustyroger

I wouldn't know where to start looking up Chevy piston facts and figures.
Quite clearly you do, with your laudable history of engine building so you should.


Back in the heyday of building monster mini engines often other manufacturers rods and pistons were part of the mix. I doubt that was needed for American V8 iron, all manufacturers made 400 cu.in.+ engines so there wasn't the necessity.


Roger.

cutlassefi

You're assuming.
Not all 400c.i. engines are the same, different bores, strokes, deck heights etc. So finding rod and piston combos is no different than what you said you did with mini parts. Find out what the deck height is then compute the needed piston heights and rod lengths from there. Again easy math.

rustyroger

The point I'm making is I never heard much of Mopar parts going into an Olds engine, or Chevy/Ford hybrids.
But stretching a 1275cc BMC "A" series out to 1545cc (it has been done), means you can't buy pistons made by BMC for it, or a crankshaft or rods either.
The one I read of had a custom ground from blank crankshaft, Simca (French) pistons and Ford rods.
I didn't think any domestic engines had interchangeable parts from make to make. Not 283-350 sbc engines or 330-403 Olds, but as in a 350 Chevy, Buick or Olds have no parts in common.
Everyone has their favourite engine, some would consider nothing but Oldsmobile power, others might prefer offerings from other parts of the GM stable, or Ford, Mopar or even AMC. They all made engines of similar sizes which could be built to produce much more power than they left the factory with, with varying degrees of difficulty and cost.
My reasoning is you don't need the extra work of modifying another makers rods or pistons to fit your engine when you have perfectly good ones off the shelf designed to fit your engine and work with your compression, cam, head etc.


Does anyone know of engines built with other makers parts in North America?, I'm not saying it has never been done, but I do think it would be very much the exception.


Roger.

Octania

In "The Fastest Indian" my man made his own pistons. As in, cast them in his garage.

And set the record.

He DA MAN.

schoenchen144

I have not been here for a while...something about having to work almost every day or something. Anyway, thanks for all of the input on my question, but sadly, now it does not matter. I kinda hurt the engine recently and she wants to puff smoke when i get on it hard, so that moter will have to come out for a rebuild and i may just put in a 350 i have for now. Now I know this would be an oppertunity to put her back to the factory engine and tranny, however, finding and then getting a 455 is somewhat of a challenge where i live here in Kansas so for now, it will have to be a chevy engine that goes back in. Thank you for your support!