taguy16

I'm trying to return my previously (poorly) carbed '89 Z back to the original TBI configuration and can't seem to find bolts that thread into the coil bracket holes of the TBI manifold I got for my car's engine. I was wondering what the original size/thread pitch of these bolts was so I don't try so force the wrong size/thread pitch bolts in the holes and ruin the threads in the delicate aluminum casting. They look to be either 5/16" or 8mm holes: I have tried both coarse and fine thread 5/16" and an 8mm bolt I have in my bolt collection (don't know the thread pitch) but no go. Part of the problem could be there is some paint in the bolt holes, but I still need to know the right bolt size so I know what to chase the threads of the holes out with.

It's too bad they didn't stick with only Metric or SAE fasteners when they built these cars. It's seems since the late '70's there has always been interest in switching over to the Metric system in America, but there has also always been a great deal of resistance to do this even though it would make measuring and calculating things so much easier. So now we're stuck with the mess we have of not knowing what we're working with half the time.

Thanks for any help.