Q: Rearend Swap 1967
Does anybody know if a 1969 Lemans rearend will fit in a 1967 Firebird?? Any modifications needed?
A: A body cars use _coil_ springs in the rear, whereas F bodies use leaf springs.
The A body housing will be wider than the stock Firebird piece, and will require narrowing, or special offset wheels. You can cut off the perches and mounts from the Lemans rear, and weld on perches for the leaf springs. But this is a lot of bother for a 10 bolt.
I’ve read that some 1st gen owners use the 2nd gen rear, which is a bit stronger. But this rear is still wider than your 1967 rear. I don’t know how much wider, or if the spring perches have the correct spacing.
A: I just bought a 1977 Firebird 3.23 Posi (Code PX) Rear for a 1969 Firebird. I too was told that these are wider than the 1st gen rears. However, I have measured both rears, more than once, and in more than one way, and could not find any difference in the OVERALL width.
Since I had heard so much of this “the 2nd gen rears are wider” stuff I still couldn’t believe my measurements so I checked my AMA spec for Track Width Rear and the number is 60 inches, same goes for 1968’s. I didn’t have a 2nd gen spec but thankfully one of you on this list did and guess what? The number is 60 inches for 6″ rims and 60.3 for 7 inch rims. I’m now convinced that the 2nd gen rears are NOT wider. I’d be glad to hear anyone else’s 1st hand experience.
As far as the Spring “perch” or mount that is welded onto the axle tube, they ARE indeed wider on the 2nd Gen by about 2 3/4 inches. I will have to have these cut and re-welded.
Last thing, 1968-1969’s and 2nd Gen’s all used multi-leaf springs so if you get a 2nd gen rear for a 1967 you’ll either have to convert to multi-leaf of use “perches” from your old rear because the depth is different.
A: I have used a 2nd generation rearend in a 1968. It’s only about 1/2 wider on each side. The existing spring perches must be removed and new one welded closer to the differential. Care should be taken to properly align the pinion angle. The drive shaft will have to be shortened. If you use a rearend from a 400 transmission car you’ll need a big-and-little U-joint as well. Aside from the cost of the rearend itself, The costs were as follows: new perches $25; drive shaft work $35; U-joint $18. Good luck.
A: I’ve got a gto rear in my 1967. had to add spring perches, and clean up the coil spring stuff. not many 12 bolt rears around, so its worth the work for a 12 bolt.
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Content last modified: January 22, 2014 at 10:02 am