Yes, and the reason why is because the block is too narrow for a standard bellhousing as it has only 60 degrees of opposition between the cylinders. GM made special versions of the th200r4 and the 700r4 for these engines. So, no I don't think you can get a th350/400 to bolt up, but there are rear wheel drive transmissions that will. If you want a th350 because you don't want overdrive, you may want to go with a manual. S-10's are available with I think a borg-warner t5, so you could take the bellhousing and I think a borg-warner super t10 will fit.