Can you read the casting number on it? In a lot of cases, the small bellhousing was aluminum and the large one cast-iron, but not always. However, if it IS cast-iron and not "COBRA" lettered, it's probably a 164-tooth.

 

OK, seeing as I have a new 157 tooth in my garage, if it is the 164 tooth flywheel can I just use the 157 tooth flywheel assuming it bolts to the clutch set up and I get a corresponding starter?

 

You can NOT put a 157-tooth flywheel inside a 164-tooth bellhousing or vice-verse.

 

Well it will be going into a 1986 T5 bellhousing not my current three speed one

 

Bad idea. Stick with the bell you have now. You don't even need to remove it to install the T5. Using the Fox bell is theoretically OK, but does create problems. You already have a starter, clutch, and linkage that works. Why mess with that?

 

Pop the starter out. If the ring gear is flush with the wheel, 164 tooth. If it's offset by about 3/8", 157 tooth.

My guess, you have a 164 tooth.

 

Will both the 164 and 157 fit in 1986 t5 bell housing? And like I said, couldn't I just use the 157 in the t5 swap assuming I use the t5 bell and proper starter?

 

No. Again you have to have the flywheel that matches the bellhousing, and vice-verse. While a 157-tooth flywheel will physically FIT inside the 164-tooth bellhousing, you won't find a starter that will work with that combination.

Chances are quite high that if it's a '86 Mustang bellhousing that it's a 157-tooth type.

 

Okay thank you so much for the advice. It sounds like the 157 tooth is the way to go since I'm using a 86 model bell housing. I trust since the automatic c4s have 157 tooth count, that I'm safe to use a stock type c4 starter

 

Yes, but you could also use a late-model PMGR starter for better performance.

 

One advantage to using the T5 bellhousing, less tolerance stacking.

 

well i figured while i had everything out i go ahead and replace the clutch disc and pressure plate along with the flywheel, seeing as they are quite old. I want to go with the t5 bell because its cheaper to use a fulcrum than buy an adapter.

 

That's what I'm doing I bought the Ford Racing 157 tooth 28oz billet flywheel that's used for the T5 swap according to cjpony (its what they use on their 67 T5 swap). Using it with my 92 T5 and bellhousing.

M-6375-A302B Mustang Ford Racing Flywheel Steel 157T 28.2 Oz Balance 289/302/351 1965-1981 | CJ Pony Parts