Hi, wondering if anyone knows if a 3987445 n.o.s. brake drum would be the same as the ones for my 1970 8.2 Buick rear? they are listed for 70-72 chevelle and 74 nova.
I did a google search, I may have answered my own question? this part number comes up as a front drum so this will not work for my rear correct?......... Man what the heck did we do before the internet.....lol.
The Buick rear drums are different as they have a larger finned skirt that goes past the backing plate offset. Chevy only goes up to the backing plate. Just another one of those Buick Olds added extras for more cooling etc. BUT physically the Pontiac and chevy drums will work - Pontiac will be the best fit as it has the correct hub register (2.78) and stud holes Chevy has a 2.81 hub register and the same stud holes 7/16 x 20 Jim J D Race
wheel and drum are centered on the hub register. part that sticks out in the middle of the axle shaft wheel bolt pattern
Thanks - interesting. So with the chevy drum the drum could be slightly off center and cause a vibration or uneven braking? Have you (or anyone?) run across that?
huh, yes very interesting information. I never would have guessed. Thanks for the info. so a chevy drum will fit a Buick but a Buick drum will not fit a chevy?
correct. And you can fit a BOP drum on a chevy you just need to open up the register hole with a deburring bit on a grinder etc. Just ream it around . The part stores are selling 8839 drums for all the old cars and they are just not correct they are for metric stud rears from 1982 -2004 etc. YOU can use them but the studs are sloppy and the hole for the register needs to be opened up again.
I remember my first experience with OPGI. I saw they had an aftermarket distributor listed for a Buick 455. I called them a couple of times before I purchased to verify the application because at the time no one else had one for a Buick. Yep, they checked it out and they were sure it was for a Buick. When I received the unit it would not fit. I determined it was for a Pontiac 455. I called OPGI and of course OPGI thought BOP 455s are all the same.