451 BB build OPINIONS!!
Your stock 440 crank is the hp cap here. Dont build for more than 600 hp as the crank will crack.
You can port 452 heads to flow about 270-280 and that will get you 550 ish hp.
Maybe some shumacker headers or some dougs. Stay away from the tti,they charge too much.Manifolds are restricting.
Road racing you may want to consider a floating oil pickup.