76 mk 4 gear change 2.75 to 3.25

Got me a 76 Mk4 with fresh 460 with all the fun stuff done. Standard rebuild on the C6. Now for the gears. Want to change from the stock 2.75 to 3.25. Will this luxury land barge take off nicely or will it become a sit and spin? Is there something else I should have done to the tranny? Also, is there such a thing as reasonably quiet gear sets and where would I go to find these?

I HAVE A 78 TOWNCOUPE THAT HAD THE SAME GEARS IN IT...SWAPPED TO A SET OF 3.70s AND IT NOW MOVES THAT 5000 LBS WITH LOTS OF FUN ...CRUISE RPM IS STILL ACCEPTABLE AND REALLY COMES OUT OF THE HOLE WELL..I WOULDNT GO ANY HIGHER THAN 3.70s AND WOULDNT GO ANY LOWER THAN 3.50s...THAT IS IF YOUR LOOKING TO JUST STREET DUTY....JUST MY 2 CENTS...

What are you trying to do with this car? Straight cruise, street/strip style fun?
We have 3.00's and they are great for cuising and from a roll blasts.

We had a set of 3.50's in it and they work very well. But if you are going to do a lot of highway, they were a little low, even with 29" tires.

I have a set of 3.25 gears coming, but haven't got them in yet.

How much power is your car making? If its around 350hp, with all the weight these cars have, I wouldn't be worried about huge traction problems.
Are you going to install some kind of limited slip, trac-loc or detroit locker?
Do you have traction problems now?

I have 3.25s in my Thunderbird now. With 29" tall tires, I am turning 2600rpm @70mph. The car does like to spin a lot, which is surprising because the car is only around 300hp. I had 3.50's in the car before and it only raised the cruising rpm up to 2800. I will be rebuilding the rear in a few months and I think I am going to try a 3.50 trac-loc this time. We will see if it spins or sticks.

Got me a 76 Mk4 with fresh 460 with all the fun stuff done. Standard rebuild on the C6. Now for the gears. Want to change from the stock 2.75 to 3.25. Will this luxury land barge take off nicely or will it become a sit and spin? Is there something else I should have done to the tranny? Also, is there such a thing as reasonably quiet gear sets and where would I go to find these?

If your rear is noisy, there's something wrong. At least that's what my wife says.

A lot will depend on the converter in the car, and rim weight/tire width. My Cougar has 3.5s with a trak loc on 275 50 17s (I think thats a 28.5" tire).. If I try to launch at 2500 RPM to WOT, it will sit and burn for a few seconds before moving.

If I were driving the car on the highway all the time, I'd go with 3.25s.. it's tolerable, but just a noisy ride.

i dont understand why it should make noise?? ive put a bunch of rears together and not one of them made noise..unless your speaking of gear whine ..but i havent gotten any of that at the 3.25 range...now the 4.70 and up ive gotten a little gear whine but only for a short window of higher rpm...am not trying to step on anyones toes but ...what gives??

By "Noise" I was interpreting it as "engine noise"

By "Noise" I was interpreting it as "engine noise"


i stand corrected....