July 14, 2006A couple months ago, I purchased a '90 7Up 'vert. It had a blown motor, but came with another 20k mile remanufactured motor. The reman motor didn't have an intake on it. I am assuming it was originally out of an Explorer b/c it had the big plastic lifter holdowns instead of the typical Mustang dog bones. Also, it had the plugs in the back of the heads which would normally be open on a Mustang for the emissions crossover tube.
Originally, I was thinking that the heads were GT-40s. If I recall, GT40s have 3 lines cast into the front side of the head and GT40Ps have 4 lines...?
I decided to rebuild the stock '90 motor and used the heads off the reman motor with the machine shop's advice. I could NOT get the threaded insert plugs out of the back of the heads. In other words, I cannot run an emissions crossover tube on the Mustang b/c of this. I don't think this will be too much of a problem, but I need to make sure I have the right plug, so the fuel is completely burnt.
My question is what spark plug do I run if I have no idea what the heads are out of? I just put the car on the road and want to make sure it's going to pass strict MA emissions.
The car will be going to get inspected next Wed., so I need to find out ASAP. Thanks in advance for your help!