I replaced the optispark in my 94Z28 with an MSD one. The car started up fine, but overheats after about 10 minutes. The heat to the car doesn't seem to work either. I didn't hit the optispark with a timing gun first. Was i supposed to? I thought it just plugged in and worked fine.

Thanks for the help

 

when you take the original optispark off, youre supposed to take the front cover off and mark where the rotor is, and when installing the new one, its suposed to be in the same place

 

The timing is computer controlled therefore a timing light is usless in the situation. Also the dowell pin will only let you install the opti one way. You may have an air pocket in the cooling system. That may be the reason for the overheating and the non blowing of heat from you heater. Bleed the system of air and recheck the fluid level and go from there.

 

What should I disconnect in order to bleed the system?

 

there are bleeder screws in the cooling system lines, which allow you release air from the system

 

I opened one of the sets of bleeder screws and it still overheated. Is there another set beneath the car as well?

 

Did you run the engine till coolant came out of the bleeder valves? There are no other bleeders except for the ones on top. Make sure you fill coolant directly into the radiator instead of the overflow container.