hey guys I am picking up a new rear for my car. THe guy i am buying the rear from is telling me that it has 3.73's. I never knew that 3.73's were ever an option from the factory. Anyway it is a 1987 formula 9-bolt rear with disc brakes. I would say odds are it is most likely has the 3.45 ratio, or am i wrong, did 3.73's ever come from the factory in the 9 bolts in 1987?

 

No they did not.

It's not impossible that somebody changed the gears, but it's highly unlikely. I's estimate that there's less than 1 chance in 10,000 that it is what he says it is.

Pull the cover and look before you lay your money down. Now that you know that almost for certain the seller is lying, you'd be a fool not to. Otherwise you're likely to end up with a 2.77 with a toasted posi and the old crappy cast-iron brakes.... a giant paperweight.

Rule #1 of buying used cars & car parts: Never believe a single word out of the mouth of the seller, unless you can verify it independently.

Rule #2 of buying used cars & car parts: If it sounds too good to be true, it's not true.

 

9-bolts never had a 3.73 available. Thats a 10-bolt ratio. 3.27, 3.45, 3.70... those would be more like 9-bolt ratios.

 

Nope, not from the factory, not 3.73. Is it a 5 Speed???

John

 

the rear from the formula is a 5-speed, but as soon as i get to see the rear, i am going to open it up and check out the gears myself. if the rear does have 3.73's then the stamp on the ring should say 41:11 right?