I was going to stay out of this, but it’s just too hard not to throw in my two cents.

First off, welcome to CHR. We’re really a good bunch of hot rodders and you’ll find a lot of valuable information on this site. You’ll also find that there are a lot of opinions as to how things should be done. One of the areas where you’ll get very strong opinions is in the engine build section with SBC probably getting the most attention. Don’t know if that’s because there are more SBC “experts” or if there’s just so many small blocks out there that everyone has become a “self-proclaimed” expert.

Your post reveals your desire to, “make at least 400 horsepower without nitrous on a stock bottom end and stock heads.” I could write a book on that statement alone, but here’s a few pointers to you started:

1. Get us the casting numbers on your engine and your heads. The venerable 350 will make 400HP easily with the right components – but we need to know what foundation you’re building on. If you tell me you have GM 12558062 Vortec heads I’ll get real excited. They typically flow 225 to 230 cfm at 0.450- to 0.500- inch lift and are one of the best factory heads on the planet. If you’ve got 3998991 low compression smog heads – 1.72 intake and 1.5 exhaust valves with 75cc combustion chambers I’m not so excited.

2. Bored .030 over is good if you’ve got flat top pistons. Rebuilders typically install cast, dished, low-compression pistons unless they’re directed otherwise. As such, compression is in the 8-8.5:1. Not enough to make good horsepower.

3. In my opinion, static compression ratio needs to be 9.8:1 or higher to make good HP. Others will differ, but most will agree that without knowing your SCR, you’ll be spinning your wheels and wasting your hard earned dollars. To calculate SCR you need to know:
• Bore-- The diameter of the cylinder bore
• Stroke-- The distance the piston travels in the cylinder
• Deck Height-- The distance between the top of the cylinder bore and the top of the piston, when the piston is at TDC (Top Dead Center, or at its highest position
• Compressed thickness of the head gasket-- varies with gasket manufacturer and application
• Piston top volume-- If the piston is dished, domed, or flat it affects the compression ratio.
• Combustion chamber volume-- How much open space (in cc’s) is in the head above the cylinder
Once you have the above information, use this handy little calculator and fill in the blanks - http://www.rbracing-rsr.com/compstaticcalc.html.

The easy variables to change are the head gasket thickness, head (combustion chamber volume) and piston style - in that order.

4. Regardless of your heads, the Edelbrock Performer RPM and a 650CFM combination is a good value. Yes there are others (Victor for one) – but this combo is a great bang for your buck.

5. Cam – lots of variables here – transmission, rear-end ratio, stall speed of converter (if automatic), weight of car, what operating range do you want? A very safe bet is Edelbrock Performer-Plus cam and lifter kit - $124.95 Summit Racing Part Number EDL-2102. It’s a hydraulic flat tappet with an idle-5,500RPM range. Intake duration at 050 inch is 204 degrees; exhaust duration at 050 inch is 214. Advertised intake duration is 278 degrees and exhaust duration 288 degrees. Valve lift with stock 1.5:1 rocker arms is 0.420 int./0.442 exh. Very safe.

6. Headers and 40 series Flow Masters and you’ll have some nice sound too.

To recap:
• Get your SCR to 9.8:1 or higher
• Heads that flow well (Vortecs are winners)
• Flat top pistons
• Thin head gaskets
• Moderate cam
• Edelbrock Performer RPM and 650/750 vacuum secondary carb
• Headers (1-5/8, four into one)
You’ll have 400+ horsepower and 425+ f/lb torque

Good Luck,
Glenn