[Supras] mk3 block differences?

[Peter]

I looked like oldfaithful last night as we were on our final tuning run, lol.
120 over the bridge and a geyser of steam spewing behind me. I imagine it would of made for a great picture. So anyways its rebuild time, I knew it was inevitable just didnt want it to be under these circumstances. 
Question is, is there any differences between the mk3 blocks in later yrs vs the 88? and no I dont want to hear anything about the 1 or 2js unless someones got one for real real cheap.