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Old 03-15-2017, 09:06 PM   #1
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SM-420/Pontiac engine

Will the SM-420 tranny bolt up to a Pontiac 389 or 400 block? This would be in a '65 GMC.
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Old 03-16-2017, 01:11 AM   #2
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Re: SM-420/Pontiac engine

It should bolt right up to a Pontiac bellhousing as long as the center bore is 4-11/16". But then you have the issue of having to support the rear of the trans since you will no longer have a crossmember mounted bellhousing. The SM420 does not have provisions for a mount.
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Old 03-16-2017, 02:17 PM   #3
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Re: SM-420/Pontiac engine

Might make one of these work. And use it with the stock bell. Don't know if you could make it work with a manual though? Find a sm465 that has a mount?
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Old 03-16-2017, 08:42 PM   #4
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Re: SM-420/Pontiac engine

The Olds & Poncho, bolt the starter to the dr side of the block . Buick must be on the pass side , as the Chev all the BOP stick bells that I have seen , had provisions for a starter on either side? The adapter wont work for this app, but would work on an auto trans swap. You could use the BOP bell, & swap to a car type trans, that mounts @ the rear cross member under the trans....or possibly use a scatter sheild, & weld the mounts on the bottom to mount to your bell cross member. longhorn
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