The 1GR-FE block is definatelt different than the FWD 2GR-FE block. I do not know about the 2GR-FSE rear wheel drive block. I am guessing that the internals might be swappable between the rwd motors but not to the fwd motor. My reason for this guess is the flywheel bolt circle is much larger in the 1GR than the fwd 2GR. the tranny mounitng circle is so loarge on the 1GR that the fwd 2GR tranny will not bolt to it even with an adapter, as the axle will not clear the 1GR block. ( from my attempts to mate a solara E series tranny to a tacoma 1GR)
I would love to get my hands on a 2GR and compare some differences.. if i could get the internals from the 1gr into the 2ggr fwd block i could make a fwd 4.0 v6 that i could then fit in the back of my MR2. As it is, there is no tranny option that will work with the 1GR set up transversely. All of this is contrary to the popular but wrong info floating around that all GR blocks are the same.
