Originally Posted by xaircav
They will bolt on but the 305 is 4" bore block and the valves may be shrouded by the 283's smaller bore. The 305 heads also have thin decks and large chambers.

Think again- - - - -the 305 has slightly under a 3 3/4" bore, with the same 3.48" stroke as a 350. The 305 and 350 crankshafts are not interchangeable, however, different balancing. The head casting number I recommended has a 58CC combustion chamber, almost identical to the high compression 283 head. Put 1.6" exhaust valves into the 305 head, do a pocket port job, and they will run rings around any 283 head. They're also 50-something years newer and a lot easier to find.
Jerry

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