[Mickeymotormount]

As far as I know, 1968 and later blocks were machined for the spin on filter. This was one of the few changes to the architecture of the small block including bigger main bearing bores.

If you have a later engine with a canister, it has the special adapter to use a canister on a spin on block. These were available as an option on police, taxis, heavy duty trucks and certain marine applications. The GM part number is 3959104 for this special adapter.

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