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

1 st what speeds and not just top end speed will you be operating at and what rpms will you need to turn thru each gear, tracks with a lot of slow tight turns is gonna benefit from low rpm power than tracks of a higher average speed a long straight aways.

Once you got an idea where you need power (rpm) then figure how much power at these rpms is needed will help decide displacement. Then we can figure parts to get that power where needed.

Eg. if you needed peak power of 350 hp at 6000 rpm, that's 306 tq @ 6000 which tq at peak hp is about 90% of peak tq give or take a few % = so the engines peak tq is about 340 tq, 1.25 tq per cid is a decent obtainable number. 340/1.25 = 272 or 273 being closest engine if around 350 hp around 6000 was the goal. Or a terribly inefficient tq:cid of 1.07 tq = 318.

I think you said you want 300-400 hp at 6000-7000 rpm a 318 would make 380-480+ hp at those numbers a 360 probably will make 450 to into 500s + hp. A 300-400 hp 360 is like 4500-5500 rpm peak and 318 5200-6200 rpm.

Obviously there's a lot of variables, stronger tq:cid would lower the rpms where the power is made and weaker tq:cid vice versa.