i am currently building a chevy 400. I have almost all the parts for it. Whats different from stock: .30 over, better flowing chevelle heads (i believe they flow at 1.94), higher compression (measured about 10.5:1), headers, Victor Jr. manifold, 750 cfm edelbrock carb, a slightly bigger cam than factory (though i might go to to larger one- .498 or maybe a bit bigger).

The factory specs were 260 hp and 400 ft. lbs. of torque. 8.5:1 compression.


So what kind of horsepower do you guys think ill be making??

 

.498+ lift *****

 

heads and cam seem small for a 400.. 300/315fwhp

 

what if i stepped up to a .500+ cam?

 

and my numbers for the heads might be slightly conservative

 

Can you not get a set of vortec heads? A lot of people run those heads on 400's and could give you a good idea of how much power you would make that route.

whats the casting # on those heads you plan on running??

 

Heads are killing it and the cam is so so. Id say under 300 flywheel hp

 

You don't have near enough information to formulate a good guess.. but, my guess (shot in the dark) is you're probably making anywhere from 270-330 HP at the flywheel. Your only saving grace is your displacement because your heads are definitely not helping you at all. Lift is such a miniscule aspect to cams that it shouldn't even be bothered mentioning by itself. Buying a cam based on lift is ASKING for huge problems.

You've got some work to do before you ask this question. Right now we're all just guessing and you're not even sure of all your specs. I can tell you this much, though:

1. Want power? Cylinder heads are key. Yours aren't performance heads by today's standards. They make great doorstops, though.
2. That carb isn't helping you any. Good for a grocery getter, not good for trying to make power and doing it consistantly. It'll do for now, though.
3. You're going to need to feed those cubes to make the power it's capable of making.
4. What exactly are you trying to do with the vehicle..

Power costs money. So the big question is - how deep are your pockets? Play smart with your money and you'll come to find out power is easy to make for a relatively low(er) cost.

 

Your skipping critical steps.To know for sure you have a workable engine is key.Compression and leakdown tests help.400's are known for cracks/warped decks/oval bores.