i have a 396 chevy big block. what would i need to do to get 600-650 crank horsepower out of it? i know id need heads and a cam but how big? it already has 11-11.5 to 1 compression. also itd have to be suitable for road racing. not alot of road racing tho. mostly lots of street beating.

thanks Jesse

 

naturally aspirated by the way.

 

if yor wanting to do it all engine no nitrious or blower or turbo, and still make 600 to 650 yea it can be done but its ganna be pretty radical and its not ganna want to drive on the street verry well, if it were me i would build a 400 to 450 horse engine for nitrious and then spray to get your 600-650 thats your better bet for what your ganna wanting to do with it. and it will drive perfect on the street just my .02 cents

 

Check out Brodix's website and check out some of their BBC heads. They flow insane amounts of air. Also increase your cubes if possible, there are small blocks with more displacement than 396.

 

This would be a good time to save for a year or two and take it to an engine builder. You're asking a lot from <400 cubic inches. It's not impossible at all, but it's out of the reach of the average hot rodder.

Ben T.

 

You can still make your HP goal of 600 HP. You will need a set of good oval port heads like the Dart oval port 265 cc intake runners. A Victor Jr intake, 850 cfm carb (Mighty Demon, Quick Fuel, Holley HP w/billet meatering blocks, or Proform), 1.7 roller full body rockers, boring the block to the max streetable, and a matching solid roller cam. The cam that is going into my 69' Chevelle SS 396 is made by Erson Cams. It is going to be fairly streetable and these are the following specs:

Advertized Duration-------282*/288*
@ 0.050" cam lift---------253*/259*
lift after lash------------.646"/.646"-----gross lift .680"/.680"
Lobe Sep. Angle---------110*
Int. Centerline----------107*

 

I'd try it with a bigger motor. If you're going to run a BBC you might as well offset the additional bulk and weight by running more displacement. The bigger your motor the lower you can spin it and still make the power you want to.

I'd seriously like to see you talk to a local engine builder. Find someone with an engine dyno who builds motors and let them help you.

A solid roller cam in the 260s @ .050" and any nice set of ported aluminum heads should get you over 600 at the motor. A single plane and a 850 double pumper could finish it off.

I'm guessing you also want to run this thing on pump gas? If you're not wanting to use race gas, that makes it a lot harder as you'll not have compression on your side.

Does this motor have to be very streetable? Can it idle at 1500 RPM? If you want to do "street beating" like you said on pump gas, I suggest a bigger motor.

If it doesn't have to idle well and could be run on at least some race gas, then you coud meet your goals even with a smaller 383. Your extra 13 cubic inches for your 396 is coming at the expense of a lot of weight.

Ben T.

 

He could also buy a internal balance 4.00" stroke crank fairly cheap (Scat, Eagle, etc. cast steel crankshaft) and make it a 438 cid motor. The extra stroke would help offset the cam for rpm and use his stock block. Around here it is preaty hard to find BBC cores and they are usually not cheap. At least the stroker piston's, that would have to be made specially, would be cheaper than a new block. These are just some alternatives for a budget build motor.

 

I would definataly shoot for more cubes

 

600-650 HP with a 396" is going to need some really good heads and a fairly big cam profile. I've built several 650-700 HP 477" and they did not like being driven. They run hot and have pretty big springs. Plus the less size you have the higher u usually have to spin it. That's one reason why 500-600 inch street motors are so popular the last few years. Good luck, anything is possible, but not cheaply.