Swapping out Olds 12 bolt for BOP 10 bolt

Post Reply
Newbie Poster
Posts: 1
Joined: Fri Aug 31, 2012 1:33 am

Swapping out Olds 12 bolt for BOP 10 bolt

Post by lemans1 » Fri May 09, 2014 4:03 am

I have a 67 Buick Sport Wagon with the Olds 12 which is an open rear. I would like to swap it out for a 66 Pontiac posi rear that i have. My questions are 1. Do they use the same upper control arms? 2. Is the width the same from end to end including drums? 3. Will the coil springs fit or would i need to buy new ones? Any help would be greatly appreciated.

User avatar
Average Poster
Posts: 849
Joined: Tue Nov 13, 2007 7:56 pm

Re: Swapping out Olds 12 bolt for BOP 10 bolt

Post by monzaz » Mon May 12, 2014 1:57 pm

Well in thwe BOP (Buick Olds Pontiac) rears the 67 rears (55.25) were wider than the 64 65 66 rear (54.25). BUT we have found late 66 rears with FLAT bolt on springs with the same late model width rears (55.25)

SO -

As long as you keep your same upper control arms and lower control arms with the car you will be fine. The springs will depend on the perch you have on the rear, The early springs will fit the 67.... BUT the coil will be slightly larger at the rear end mounting perch area around the raise mounting area which could cause a slight clank in the corners and hard launches. AGAIN if the perches are the same you will not have an issue.

Width will depend on the physical measurement of the 66 rear. if it is a late rear it will be 55.25 if it is a early 66 it will be 54.25. If your using a stock tire wit stock rim it will not even make a hill of beans difference.

J D Race
J D Race

Post Reply