I just got a 400 block and Im looking to turbo the motor. I was wondering what you guys thought a good set up would be to run around 600hp to the rear wheels. Im going with forged 6" h beam rods and reverse dome pistons but idk what size or cam and crank or what heads. Since they should be steam drilled. I also have a 650 eldelbrock or a 700 holly rebuilt for blow threw.

 

First thing I would do with a 400 block is have the cylinder walls sonic checked for core shift and make sure they're thick enough all over to support the 600 HP goal - that's getting a little iffy on a stock block that's not cast perfect.

If it's a street car - have the deck plugged and milled to prevent it from cracking - if it's going to be primarily a drag car consider a half-fill of hardblock to stabilize the bores.

Go with a steel billet main cap setup that runs splayed studs - you'll have to have it machined to accept the splayed main caps but it's worth it on the 400's at that horsepower level.

for 600 HP on a 400 - I'd be looking at AFR 210cc CNC heads for mainly street duty or their 227cc heads for more of a strip engine with better upper RPM potential.

Cam choice is going to depend on the full combo, where you want to build the horsepower as well as how well the exhaust will flow (i.e. more backpressure from the turbo setup will require exhaust valve to close sooner to prevent intake charge dilution, etc.) Once you've figured out the RPM goals, then found head flow and done some basic math and ran some cam profiles through and figured out how much boost you'll be running to support 600 HP then you can start matching the parts...

 

Wouldnt do that to a GM block no way
Get a SHP

 

That was the advice from my machinist too.

 

I also have a 350. Ive seen stock blocks push the 600 range without turbos. Also I dont understand what you mean by shp, I only know that as shaft hp. If thats what you mean are you saying run all motor, or what?
Im not looking at running any more than 15 lbs at around 55-6500 top rpm. Its going to be a street car. We are building it to stay with my buddies 07 gt500 that has 600 to the wheels maybe a little more. I want to run a no more than 9.5:1. Also I want a mild loap sound to it.

 

SHP = "Special High Performance" - it's an aftermarket block cast by DART - they are stronger than a 'stock' engine and are built to handle more HP and abuse while keeping costs down - they say they're good for ~500 hp builds if I recall as they're wanting to sell their more expensive block for the bigger builds

The 350's have better cooling between cylinders as they are not Siamese'd together in the middle and typically have thicker walls for better bore stability so I'd start with a 350 if you've got it and I'd add up the machining costs of a stock block vs getting an SHP block prepped (still takes some prep/checking but a LOT less than a stock used block)

 

Machining it wont cost me the 2500 it is to buy and ship the block then what it costs to get it ready. Ive already looked at the dart blocks. I could understand buying one if I didnt have an engine or two already. I just cant see speanding that much if I dont need it.
So really I guess what im asking is whats the best set up for high horse power with the ability to drop compression for a turbo or supercharger.

 

Go over to "the turbo forums" (http://www.theturboforums.com/) and take a look around at the SBC and the "Builds" sections and look at the guy's combos that have dyno'd them - plenty of SBC combos over there pushing 600+ HP. It's not terribly hard to get a reliable engine using a well prepped stock 350 block, 4340 crank, H-beam rods, forged pistons and good pins and about 8.5:1 compression, heads that flow 290-300 CFM at .500 and a decent turbo setup.

 

Keep it simple, keep the rpms low, and use quality fasteners

2 bolt block will handle the hp for alittle while but the caps may be walking by then. I'd be more concerned about cracking lifter valley in 2.

I wouldnt put to much into the rotating assembly. Good pistons maybe, any I-H beam rod should do, and I would prefer forged crank but perhaps a stocker would hold for alittle while. Save for a new block, an SHP fully machined should run 1800 bucks to your door. Call Carl at cnc blocks northeast.

Anyway, do any good aftermarket 195 head, cam around 230 deg at .050. Rev to 5800-6K rpm, 10-12 psi with a good 76-80mm single and you got yourself a 600whp car. BW S400 type turbo should be good for a budget single