I have used a crank balancer from an 83zx on my daily driven 79zx and have had no problems with it, its been about a year now!! Also, the washer used is different along with the timing indicator the bolts to the block. Might want to see if the indicator from the 79 can be used on you car. I had swap the indicator on my 79zx to accommodate the crank balancer from the 83zx to fit.