Dodge 318 pistons are a close match at 3.910 standard bore (ends up as .035" over for the Pontiac 350).

CD is 1.700, pin diameter .981 for the Pontiac 350.
CD is 1.720, pin diameter .985 for the Dodge 318 (L3013F).
CD is 1.739, pin diameter .985 for the Dodge 318 (L2406F).

Measure your deck height and CD (compression distance) with your stock pistons. You may be able to have a zero deck without surfacing the block. The pin end of the rods will need to be opened up to the Dodge pin size. Both pistons are flat tops.

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