Not sure what all it will directly bolt to and what engines you would need a different bellhousing, but I've been researching a t56 swap for my truck. From what I hear, those 5 speeds that are behind the 4.3 and 4.8 have pretty low power handling. Maybe fine behind a bone stock 350, but much more and it might decide to blow up.
It will for sure bolt directly to the 350/305 engine, since in the 1/2ton variation they used the same tranny for those engines. As to the newer LS Series motor i believe the newer Vortec trannies are the same between the 4.3L and 4.8L however you will need the wiring for a manual tranny if you are swapping over from an auto to a manual.
Al, I am sure you can leave that bolt out, yes it is the top one, I don't know about the alignment pins, they are probably ok as well;
I would guess the transmission is a NV3500, this is a one piece case and the bell housing is part of the pour.
The NV3500 probably won't stand up to the torque from the bigger LS engines; but it could be used behind the torque of the 4.8.
But, it is my understanding that the bell housing isn't deep enough if you use factory 4.8 parts (flywheel, throw out bearing) an older 4.3 style clutch must be used.
However, recognizing the need, special parts are available from hotrod shops.
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