Tach issue.
 

My dad has a 91 suburban and has installed a tach. He put it with the -/+ but wondering where to exactly put it on distributor. I know on the HEI distributors there is a spot that says tach but on these TBI setups i dont know where exactly to hook up. Im sure there is probably a topic about this already and i am sorry to ask, but link me the topic if it does exist already

Re: Tach issue.
 

I did one on my '90 Fullsize Blazer. If I remember right there was an extra wire coming off the coil? Just hooked it to that and worked like a charm hope this helps. Can see if I still have any pictures.