'68 318 to carbed Magnum 5.2: Check my checklist
I'll say one thing right now: That Magnum exhaust manifold looks like it means business - even between the wider shock towers of a B-body. This is the #53006618 (RH) '92-3 Magnum manifold that everyone says flows like a header.
Clearance is just shy of 1/2" to the shock tower. I don't expect the engine mounts to flex that far.
Going to hold off doing the other side until I can order the Firm Feel box - but in the meantime, I can re-gap all my spark plugs to 0.50 in preparation for the HEI conversion.
-Kurt