I need a locker and probably a lower differential (currently 2.79:1) for the Comet. Ford rear axles are not easy to find here. If I find a 9" it will probably come from a Bronco (66-77) will the Bronco axle fit? (probably to wide) does it have the same bolt pattern? The easy way out is probably to find a 8" differential with a locker. Is the 8" strong enough to handle the 351? What is the best locker for the street in your opinion?
A Bronco rear is not the worst option to have around. It is narrow in those years. The spring pads need to be changed to fit the Mav. The wheel bolt pattern is much larger, however you can get the smaller pattern drilled into the axle flange. It would not be nearly the work you would have to do if you started with a wider rear and needed to narrow it and respline the axles. Will an 8" stand up to a 351? IMO, no. I have broken several with 302s. Dave
I would think it would depend on what your plans are as to power and driving habits. I have a 9" with a Motorsport Locker...and I love it..one of the best things I bought...but for me the 8" would have probably done fine.
Non broken original 8" in the back of my car. Still going. Plenty of launches on slicks and about a zillion miles of street driving on the stock axles. If weight and budget are a concern, stick with the eight until you need a nine.
Really? I've always had the impression that it was about 35-40lbs different. Seems like a lot of unsprung weight to me. Correct me if it's less. I'd like to know.
Without brakes, the difference is 10-12 lbs. Breakdown is 3 lbs for the housing, 8 for the chunk. If you go with 31 splines then it goes up another 3 per axle. If you go with monster brakes, the difference can be profound. You have a lot of control over something like that though. The numbers are off the top of my head... got them from a 9" custom builder, have them saved somewhere, but these are about right. I was surprised too. Dave
