400 horsepower low compression 360

I put heavily ported Edelbrock heads, RPM intake and custom-grind (.550" lift, 222° intake duration @ .050", 110 LSA) hyd roller cam on a stock bottom end 5.9 Magnum (9:1 compression) and it makes a verified 400+ HP (closer to 420). Might break 450 once I put Doug's headers on, better carb (750 DP instead of street demon) and upgrade the fuel system. It's very streetable, I drive it all the time.

What's my point? You won't make true 400 HP on a 360 with stock low-comp pistons unless you put good-flowing aftermarket heads (or heavily ported iron heads) and a high-lift (over .500") cam. Even with 10:1 it won't be easy if you're sticking with a street-oriented flat-tappet hydraulic cam and factory iron heads.

Shoot for 350 HP, that's much more realistic and plenty of power to have a lot of fun in an A-body.