I have recently installed Mac underdrive pulleys on my 85 GT. The paper that came with them said to use the stock belt. I did, and it is way too long. Has anyone else had this problem. And if so, what belt did you use to fix it. I put a new belt on it, and have contacted Mac. They just said to use the stock belt. Help Please!!!

 

not to sound sarcastic, but I would double check the belt diagram...you only switched the pulleys, so there should be no difference...it could be something so simple it doesn't seem too obvious, ya know

 

Would this help?

 

I thought 85's were V-belt?? If not maybe they make different pullies for standard rotation belts and you have the 86+ (reverse rotation) pullies? (I doubt it though) If the stock belt is way too long as you say then I agree that it sounds like its routed wrong. If you're positive its routed correctly you need to call Mac back and explain to them the stock belt definitely doesn't fit and don't let them give you the runaround.

 

but see, thats for reverse rotation serpentine belts, 85s are standard rotation unless he converted it...?

 

No, the '85 is a reverse rotation serpentine belt just like the 86-93.

 

Is the stock belt the 90.5? I keep at least one old belt nd put it in my trunk just in case...

 

I made a few trips back and forth to the parts house until I got the right one. The stock belt is 92.2". The one that fit properly was 90.0". I checked and double checked the diagram to make sure it was routed properly. That was my first thought also.

 

hmm, I guess I was thinking the reverse rotation came along with fuel injection

 

i was thinking of getting trickflow twisted wedge heads can anyone tell me if i can use my stock intake for now or will it not work with those heads

 

You're kinda in a completely unrelated thread but I believe the stock lower intake will fit fine with the twisted wedges. I'd get some other answers or do some googling before you go out and buy em though 'cause I'm not 100% on that.