Im going to put a 355 in a 86 Iroz z(auto) with approx. 330-350 HP....my understanding is that the rearends and trannys in these cars are weak so which am i gonna break first? I will have enough money this summer to get an upgraded tranny or rearend but not both and am trying to choose which one i want to do first ...i Won't be using slicks or anything...so should i either get a 12-bolt first and wait another year for a tranny or a pro built tranny and wait on the rearend?

 

well in my case, i detroyed my 700r4 with a 355 similar to yours. and my 130k mile un rebuilt but minispooled 10bolt 3.73 rear end was in perfect working condition when i sold it a few months after my 383 install.

 

Will you be running slicks or drag radials? I would replace the tranny first, but that dosen't mean your rear won't break.

On the ZZ4, only the flexplate had to be replaced so far. But it has yet to be to the drags.