66 gto rear end spring swap question - Pontiac GTO Forum
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post #1 of 3 (permalink) Old 07-30-2015, 01:56 PM Thread Starter
 
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66 gto rear end spring swap question

I picked up a 72 lemans 2.79 rear end cheap and want to swap it into my 66 gto to see if I like the shorter gear better than my 3.55. The springs for the 66 have the bolt down bottoms and the 72 is a cup. Are the tops the same between the 66 and the 72? It looks like the 72 has a pigtail top looking at the insulators in Ames and the 66 has an open top the same as the rest of the spring. The 66 springs will fit around the cups, but its not a snug fit and doesn't look too good. Advice?
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post #2 of 3 (permalink) Old 07-30-2015, 06:45 PM
 
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The tops of the rear coil springs changed for '67 to mate up to different upper spring pocket in the frame. Usually, when building an 8.5 A body rear for a street/strip '64-66 A body swap, I make sure the '64-66 car hasn't been rebuilt on a '67 frame. ( ive run across it!) If not, I'll trim the flared tops off the later rearends coil spring perches. next, will cut two slight rectangular pieces of plate steel with my chop saw. will then drill successively bigger hole in the center of each plate. I then finish up tacking and then welding the plate on top of the old coil spring perch. The stock retaining "ear" will then retain the original style cool springs.

Over the years, have also bought quite a few early 12 bolt Chevelle rears and even one early Pontiac 8.2 A-body rear that still had the upper control arm mounts, but had had been RIGGED to go into early Camaro's and Firebirds. Restoring these housings back to original A body rear configuration required carefully removing the universal leaf spring mounts, a bunch of time on careful grinding, and then careful jig placement of lower control arm/shock brackets as well as grinding and replacing the early style coil spring perches. Both brackets and perches can be replaced, but swapping the early coil spring style perches isn't something I'd attempt without minimum of good safety glasses, Dremel cutoff tool, a bench grinder, and an angle grinder. It also takes patience and a steady hand, replacing either entire perches or lwr control arm mounts, just can't get wild with the angle grinder.
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post #3 of 3 (permalink) Old 07-31-2015, 11:13 AM Thread Starter
 
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Looks like that may be the way to go, PH. They are 8.2 rear ends, and the car is an early 66 (Nov. 65 build date) that I've had for 40 years and 220k miles, so its the 66 frame. I've got the tools and the welder, but I don't trust my MIG abilities for this kind of thing, so I can farm that out to a buddy. Thanks.
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