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CamaroJesse
05-26-2014, 04:18 PM
I have a 67 firebird with the bop 8.2 and was wondering if it's worth keeping. I can not afford a 12 bolt or a nine inch. I would most likely do a new posi unit and bigger axles. Car will not see slicks or any drag racing but will get beat on at the local auto cross. This car will have roughly 375-400 hp with a six speed trans. A local shop has all fresh parts for this rear for pretty cheap and just want to make sure it's worth it.

lucky13firebird
05-26-2014, 04:43 PM
nothing to worry about, good rears, i didn't break mine with a 461, just eventually upgraded to a 12 bolt. btw there is a BOP rear used on grand prix cars, 10 bolt cover but 31 spline axles and 12 bolt ring gear. jerry titus used them in some trans am firebirds. but thats rumor has it kinda thing, and rumor also has it they are dirt cheap cause they are 10 bolt and nobody wants 10 bolts...

Nicks67GTO
05-27-2014, 01:38 AM
Im going to disagree. If you didnt have to stick money into this thing I would say run it but in this case it may not pay. When I did my research to decide if the 8.2 BOP was worth keeping I made the decision to go for a 9". The reason being that you can find all kinds of used crap for them if you break stuff or you just want to go cheap. Also the 12 bolt vs 9" arguement is null and void unless youre going for every hundredth of a second in the 1/4. The BOP stuff is expensive, weak and limited in gear selection. When I did my research I found that at stock power levels they were ok. Anything much above stock {350-375ish hp} and things can get ugly. If I remember right the only posi unit worth buying for the BOP was the Eaton unit and it is pretty spendy. The others were known for issues. Call up Quick Performance in Ames Iowa and get your 9" 31 spline housing and axles. Then find a stock carrier and pinion support. Then go for a cheap, stock 31 spline ford traction lock, used gears and set up kit and you're done. Im not sure what youre spending on axles and a eaton posi but I bet with a little ebay work and for a little more, you could have an entire 9" that will take a lot more of a beating and will be upgradeable in the future. Just my take on it.

Nicks67GTO
05-27-2014, 01:40 AM
Have you looked into the Ford Explorer 8.8 conversion? I dont know much about it but Iv'e heard of guys running them. They are supposedly strong, junk yard plentiful, already set up for disc brakes, cheap and almost always a posi traction and 3.73 gears.

lucky13firebird
05-27-2014, 03:17 AM
Second the 8.8 option.... they are such a close copy of the 12 bolt that some bearings even interchange... and they require NO new axles or anything for an f body. Just have the stock axles drilled for whatever bolt pattern you use, and drill the discs... I threw one under a 68 mustang for $135 bucks plus $35 in spring perches.....

CamaroJesse
05-27-2014, 05:34 PM
I like the sound of the explorer 8.8. Is it the same length as a 1st gen rear?

Ziegelsteinfaust
05-27-2014, 06:41 PM
There is a few different 8.8 widths to look at, but you'll need a tape measure when you go for a look.

Also if your going to use the 8.8, and do not find a width that you can live with. Get the one with the best brakes or gear ratio you can find. Have it narrowed, and add in some better axles.

My sister bf wanted one for his Nova 2, and we went to pick a part to organize the pieces. In the end we used 3 different rears to make a good base for him to quickly rebuild, and narrow.

Skip Fix
05-30-2014, 10:37 AM
When I was racing NMCAs Top Stock classes John McWhirter(orignal Comp cam partner) had a 67 442 with a tripower and a 4 speed and a 8.2. The car had been an NHRA car all it's life so it was fast 11.70s and most of us were low 12s. But if you drew John you had a 50% chance of winning because the rear would break!

The 4 pinion posi's are stronger than the 2 pinion , John actually re heat treated the ring and pinion as many were not correct.


The 8.5 10 bolts are much stronger. If you are upgrading axles you could get a GM truck housing cut the ends off for weld on no C clip ends and weld on the correct perches. That or a 12 bolt, 9".

instro84
05-31-2014, 09:51 PM
i had both a 67 and 69 firbird with 8.2. converted both to rear disk setup and added posi ran them down the 1/4 mile track for years no probs. idd hang on to it.