: Gear Swapping?



79caddy1
12-08-06, 02:03 PM
I am almost sure that my 79 sedan deville has 2.28 rear end. At least thats what I found on a site came standard in them.
Does someone make a set of steeper gears, that will bolt directly in the axle?
I don't do any highway driving, and would love it to pull out better!

jayoldschool
12-08-06, 06:58 PM
That car will have a 2 series carrier. To over 2.56s, I believe you will need a 3 series carrier. If you are putting in a new posi, that will take care of things.

Phantom&RedGoat2004
12-08-06, 08:20 PM
I hate to be the one sending crowds of people after service cars, but that's a good place to find good gears. Keep your eye out for Series 75's, Coaches, and Limo's. Every once in a very rare while, you can find one of those with posi.

caddydaddy
12-08-06, 09:53 PM
Or do what I did. I replaced the 2.28 rear end of my '79 Deville with a 3.08 posi rear from a '96 Impala SS. It even has disc brakes and a sway bar. Both of which aren't on the stock '79 Devilles.

79caddy1
12-08-06, 10:09 PM
DId you notice a big difference with the 3.08's?

I don't need a race car, but It just is slow off the line when pulling out....I will say on the highway, it really does pick up the speed.

I was wondering what rear ends would do a direct bolt up, without too much hassle. Thats why I was asking about swapping gears out.

davesdeville
12-09-06, 04:49 AM
Any corporate 8.5/10 bolt is pretty much a bolt in.

79caddy1
12-09-06, 09:55 AM
thanks!....I can check the local junk yards. I can grab one cheap.

I don't have a welder, and was worried about having to fabricate!

The Ape Man
12-09-06, 11:29 AM
Issues are lug nut pattern, driveshaft flange type and brakes. Many GM car full size lines will make good donors. Don't waste time with an open axle. Find a posi. There is more info in the archives here.

ShadowLvr400
12-10-06, 11:25 AM
Another option, is hunt on ebay, for a performance posi setup, and then have it installed. For a car that big, I'd be hunting for something a bit shorter than a 3.08. My bias would be a 3.23, or 3.42. It'll give more lowe endgrunt, but it won't comprimise highway driveability. I'm using a set 3.42's myself that I bought of ebay, and I've been pretty damn happy with them.

caddydaddy
12-10-06, 11:39 AM
For a car that big, I'd be hunting for something a bit shorter than a 3.08. My bias would be a 3.23, or 3.42. It'll give more lowe endgrunt, but it won't comprimise highway driveability.

Are you sure a 3.23 or 3.42 isn't too high numerically for a Cadillac 425? Everything I've read about them suggests a milder numbered gear so the engine pulls instead of rev.

cadder2000
12-11-06, 10:13 AM
77-83 cut out cover cadillac rear ends are a direct bolt in. The problem is most are the same ratio that you have now. In 80-81 there was 5 ratios available. Federal 2.28:1, diesel 2.41:1, California 2.56:1, towing package 2.73:1, commercial chassis 3.08:1. If you want lower, in 82-83 the V-6 offered 3.23:1 and the HT4100 offered 3.42:1. Hope this helps.

ShadowLvr400
12-11-06, 11:28 AM
You may be right about the low end of the 79's motor being able to take a taller gear. I'm basing off the LT1 which has a strong low and midrange, but gets winded up top. I know the LT1 has a 5500 redline, I don't know on that older motor of yours. A 3.08 could be a good setup for that motor, especially if it's only got like a 4500 rpm redline.

The Ape Man
12-11-06, 06:09 PM
Another option, is hunt on ebay, for a performance posi setup, and then have it installed. For a car that big, I'd be hunting for something a bit shorter than a 3.08. My bias would be a 3.23, or 3.42. It'll give more lowe endgrunt, but it won't comprimise highway driveability. I'm using a set 3.42's myself that I bought of ebay, and I've been pretty damn happy with them.

Big Cadillac engine and no overdrive in this example. SBC and overdrive are a very different story.