360 drivers side manifold A-Body?

No big port version of the early A-Body manifold. You can always open the ports up with a die grinder. But the outlet is still small, and it gets pretty skinny around the column. No matter what, the early cast iron is gonna only flow enough to support 250-275 horsepower. Beyond that, they will start really holding you back. A dual pattern cam which favors the exhaust event will help some, but there is no silver bullet. Standard early A header angst applies.