As said I would get a custom cam to build some psi, a good dual plane intake (performer RPM if you have hood clearance). dial in the dist subsystems in order. 68-70 or later HP ex manifolds (or headers if you can handle them) & mandrel bends/free flow (loud) muffs and non restrictive glasspacks alongside the leaf springs to get the noise back to acceptable. Then if that ain't enough then see about building another long block
live every 24 hour block of time like it's your last day on earth
