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I have been in the middle of a decision to change out my rear 3.08 set up in my '74 to take advantage of my new engine/trans combo. went from the stock L48/th400 (stock converter) to a 355 10.5-1 -2.20/1.60- 64cc heads and comp cam, MSD ignition, rebuilt th400 w/trans go shift kit & 2500 stall converter.
I recently purchased a used 3.36 rear diff out of a '71 and today I scored a NOS(never used in the original box) GM 3.55 R&P set with crush collar & nut for $75 (Score!)
Now I have to decide on the 3.36 or the 3.55, I am leaning towards the 3.55 as this is just a Hot rod vette for local driving and cruise nights, I have no intention of doing long or far trips on a hi-way. So just how much of difference is there between a 3.36 & a 3.55 set up?
Paul
The difference is hardly noticeable. I swapped out my aging 3.36 center section a few years ago for a much fresher 3.55 unit.
If someone had done this by playing a joke on me, I never would have noticed the difference. About an extra 150 rpms at cruise over the 3.36, and maybe the spreads between gears were a little sweeter.
On another note, since you have the ring and pinion, I believe there are two flavors of 3.55 ring and pinion set, and one is preferred over the other. I would have to re-research this, as I believe one of them has a lower tooth count, which is considered to be less desirable.
Edit... Found it 9 pinion/32 tooth ring is less desirable vs 11/39
Last edited by Big Block Dave; Feb 7, 2017 at 07:24 PM.
On another note, since you have the ring and pinion, I believe there are two flavors of 3.55 ring and pinion set, and one is preferred over the other. I would have to re-research this, as I believe one of them has a lower tooth count, which is considered to be less desirable.
Edit... Found it 9 pinion/32 tooth ring is less desirable vs 11/39
Ahhhhh Fudge.......I got the 9-32! well its still going in because that 3.08 needs a break. LOL