Are the intake insulators on a C3.2L reusable?
 

Or were they supposed to come new in the rebuild kit?

I reused mine as long as they are not cracked. You get a new gasket on each side.

Thanks Craig.

When I did my 87 this past winter, I noticed a couple of small chunks had come off one of the insulators sharp edges and then when I pushed a little on the edges of a couple, they kinda crumbled. I bought new, they weren't in my top end kit. Check yours out carefully to make sure they're in good condition. I'd recommend maybe you consider replacing 23 year old plastic with new. You might not see the crack when you tighten down and then you have an intake leak.

Yeah, I had 3 perfect ones and 3 really flaky ones. I assume the massive oil leak rotted the three.