318 with random parts.

675 heads came on 273's and 318's from 1968-1974 and were a downgrade. 273 heads are better in flow and compression.
Pistons sound like the lowest compression used from 1973-1984 (1.74 pin height)
Only 273 LA engines had factory solid lifter cams.
Almost all poly 318's and '60-7? slants have solid cams from the factory too.