Now you are talking about a poly 318? They haven't made those since 1966, then in 1967 they started making the 273's, then 318's and 340's. The polys were a completely different block than the later s/b v-8's.
Take a peek at dippy.org, they state the poly blocks can be used in an LA or magnum app...cranks can be interchanged, blocks are the same deck height, lifters are the same angle, journals are the same diameter, timing sets are the same, oil pans will interchange, distributors will retrofit, etc. Granted, I've never personally done it, but if it can be used, I guess it's another option, albeit a rare one.
