Edelbrock LD4B

IfItsGotWheels said
As I understand the LD4B manifold was designed for use on the 273 back in the 60's. Port sizes on the 273 heads are smaller than your 318. Just like everything else, manifold technology has advanced in the last 40 yrs. IMHO you'd be stepping backwards switching manifolds.

Actually 273 ports are the same size or larger than 318 heads. They are actually the same heads, but the older heads are a little cleaner and flow a little better. LD4B is better, new is not always better.