is there a difference between the two blocks? i have an 88 with a bad rear rotor and i want to rebuild it myself, maybe streetport it or something, and swap it with the motor in my 91. will this work?

 

Yes but you may not pass emissions.

I did what you're doing in reverse. I took a 87 block and put it into a 91.

The intermediate housing is different. On the 86-88 there's an egr valve on top of it. on the 89-92 there's no egr valve there..

The front cover is also different but does fit so you'll have to change between the two.

 

just get a afc and lean it out, that should help you pass emissions. i did the same thing with the inter. but i used a t2 housing because of the bigger ports.