grafddrx7

Since I need to either rebuild or replace the engine in my 88 GTU, i was wondering if the 89-on 13b with the better intake and more hp is a direct swap?

Obviously, I'll need the ECU and harness, but are there any other nightmares that I'm missing?

I know that somewhere along the line, Mazda changed the engine mount location on the 13b, and I don't want to get into a major fab job...

Thanx!!!

Rx7Nub

You will need to get a S5 ECU or a S4 front cover on the S5 block, because of the mechanical OMP on the S4. Getting a S5 ECU would require you getting an all new wiring harness aswell. But the engine itself will bolt in fine.

Icemark

Timning is gonna be an issue with the S5 block being run by a S4 ECU, as the spark plug holes are in a different spot.

grafddrx7

Since I'm new to rex's, I know that my 88 is an S4, but is 89 the start of the S5?

The engine I'm looking at is an 89, with the ECU and harness included.

Also, how much spaghetti-sorting will be involved with the new harness?

Thanx for all the help!!!