How can you tell an 89 flywheel from an 88? I mixed mine up. Are there any codes on them or is the weight difference measurable?

 

86-88 NA flywhels will be marked with n326/327 on the back, while 89-91 NA versions will be marked n350/351. The s4 flywheel will be somewhat thicker in the middle, with a counterweight offset to one side, and the s5 one will appear a bit thinner in the middle, with a large thin counterweight 3/4 of the way around.

BTW Jim, the engine arrived Tuesday, and your parts went out yesterday...man, that engine looks like it fell off the titanic. I feel sorry for you guys up there. Sorry I didnt have time to clean any of your parts, but hey, Ive had too many engines of my own to build!