I've tried to do my homework on this one but I can't seem to find a good answer. I have an 82 with the front rotor shot. the back one is still good. I checked it with a a straight edge. I bought a 84 engine from a junk yard with the front rotor and housing good. the 82 is about half a pound heavier than the 84. how long do you give it before it scores the bearing and the engine is shot again or is it a better idea to just not do it. In the meantime I plan on building a good engine, porting and what not. this is just to get me buy for a bit. Thanks for you time.

 

Don't do that, it will run but will be out of balance. There is no "getting by" in my vocabulary. ITs not smart to waste money on a half-assed engine.

Get two 12a rotors of the same year, and the harmonic balance on front of the same engine year. A 83-85 are the same. They have lighter rotors which is generally better. Don't mix and match different rotors from different years, thats a no-no. If you come across a '81-82 rotors use them and its harmonic balancer. And same goes for a '83-85 engine assembly.