I built some 396/402 BB Chevy street engines . The last one went into a 1967 Camaro SS . The car was a stock 396 car . And the guy wanted the engine to look stock . I used the stock manifolds but did a little pocket porting and install a larger camshaft . That car real ran strong . If it was mine I would install a high rise with a 750 Holley and a set of headers . I did install a 2400 hole shot converter . And the last thing would be a 373 gear the car had a 331 posi rear .