which rearend to use?

[smallblock kid]

alright so i currently have a 12 bolt in my truck with what i beleive to be 4.11 gears all i know is with the straight six and my foot to the floor and the engine redlining itll go 80 i got it to 85 once with a wind at my back and down a hill i just found a 68 rearend with 3.73s and its a coil spring like mine ive been wanting higher gears do u think that this would work out or does anybody have an idea what my gears are just by guessing any help would be appreciated

[Captainfab]

Before you get any further, I would suggest pulling the cover on the rear end in your truck and see exactly just what you have. You may already have 3.73's. Either way the oil in a rear end is one of the most neglected vehicle fluids. It could probably stand to be changed. And when you go to get some gear oil, don't forget to get a new rear cover gasket. If you already have 3.73's, they next step up is 3.42's. Also stepping up to a taller tire will help a little.

[Rogue]

I put a '68 Posi in my '64.
It was plug and play.
Higher gears made it actually driveable on the freeway.

[raycow]

3.73 was the most common rear in these trucks. 4.11 came standard with manual overdrive or could be ordered as an option by itself. You don't see very many 4.11s though, so I'm betting you have a 3.73.

If you want the truck to be quiet at highway speed with no overdrive, you should probably be looking at a 3.07.

Ray

[likaroc13]

Originally Posted by raycow

3.73 was the most common rear in these trucks. 4.11 came standard with manual overdrive or could be ordered as an option by itself. You don't see very many 4.11s though, so I'm betting you have a 3.73.

If you want the truck to be quiet at highway speed with no overdrive, you should probably be looking at a 3.07.

Ray

i thought my '66 had 4.11's, but it looks to have 3.73's...with the 2-spd Powerglide it hums pretty good at about 55-60....so i'm swapping to a 12-bolt with 3.07's from a 1972 pickup

[glendale]

ok my rear end is going out and it's time to upgrade and replace. i would really like to put star wires on my truck. so car small five lug would be great. i can weld that is no big deal. and i cant even find a truck rear around here. so what cars should i be looking for as a donor?

[lakeroadster]

Originally Posted by smallblock kid

does anybody have an idea what my gears are just by guessing any help would be appreciated

No need to guess.... As suggested by Captain Fab pulling the rear differential cover (& counting the teeth) is the most accurate method to determine gear ratio but another way to check the rear end ratio is to jack up one tire if you have an open diff, or both tires if you have a working posi or locking differential. Rotate the tire one full revolution for posis and lockers -or- 2 full revolutions for open diffs. Carefully count the number of full revolutions the driveshaft makes. This is your gear ratio. In other words, if the drive shaft turns 3 ¾ turns, you probably have a 3.73 gear ratio. Turning the tire for twice the number of full revolutions and dividing the drive shaft revolutions by two will give you a more accurate reading.

I hope this helps!

[protrash64]

Originally Posted by glendale

ok my rear end is going out and it's time to upgrade and replace. i would really like to put star wires on my truck. so car small five lug would be great. i can weld that is no big deal. and i cant even find a truck rear around here. so what cars should i be looking for as a donor?

If you are not planning on using the truck heavily, I would look for an S10 rear-end. I've seen a couple in use and they work well. If you find an S-Blazer you can get disc brakes and a 373 gear. I dont know all the width details, but gets you to the correct bolt pattern (5x4.75'').

[raycow]

Originally Posted by glendale

car small five lug would be great. i can weld that is no big deal. and i cant even find a truck rear around here. so what cars should i be looking for as a donor?

If you can weld on the brackets, there are a bunch you can use. 65-70 Chev full size, 73-77 Malibu and clones, 2nd gen Camaro and Firebird. These are all 5 on 4-3/4" bolt pattern and pretty close to stock width.

Ray

[glendale]

ok thanks guys. does anybody sell perches?

[raycow]

Here is a kit with the trailing arm brackets and panhard bar.
http://www.classicperform.com/Store/...ck/6072RCK.htm

CPP also sells the trailing arm brackets separately.
http://www.classicperform.com/Store/...ck/6072RAS.htm

Ray

[Russ65C10]

My 66 had the 250 inline six with 3.73 rear end it topped out max at 82mph. That was it, I don't think you have a 4.11 rearend but I could be wrong.

[Captainfab]

If you could find one out of a mid to late '60's Chevelle/Malibu/El Camino, they are about 1" narrower than your original rear end.

Originally Posted by glendale

ok my rear end is going out and it's time to upgrade and replace. i would really like to put star wires on my truck. so car small five lug would be great. i can weld that is no big deal. and i cant even find a truck rear around here. so what cars should i be looking for as a donor?