SB Road Racing/Nascar/Sprint Car/Reving BUDGET BUILD

the more i look at where you're trying to go, the more i'm inclined to say just go 5.9

you get cubes, good flowing heads and a roller motor from the jump. snap on a 4bbl intake, throw some garage porting at the heads, get a cam and match the springs, roller rockers if you're feeling it, upgrade the timing set and throw a road race pan at it, knock some headers on and call it done.

you'll easily reach your 400hp goal without exotic parts and have room to grow from there. it's not gonna rev to the moon, but you'll have plenty of useable power. the recipe is already there for that, and worst case if you have to rebuild the motor bearings/rings/pistons aren't going to break the bank.

i would 100% say go with an aluminum flywheel and as lightweight of a clutch/pressure plate set up as you can afford and are comfortable driving.