Factory Rear End

[Mjminino]

When I purchased my truck it was in such shambles and I don't know if a lot of stuff is 'factory', they did a $hit job on the front end converting it to a 5 lug, which I was able to get that figured out. I am about to purchase some Impala SS brackets from Captainfab to get rear disk brakes, and get the CPP 5X5 rear axle conversion for a 64. Well in all honestly, it just dawned on me, I don't know if I have a 1964 rear end or another later year (if they took the same front/rear suspension off of a later truck) Could you guys please help me out on figuring out if this is a 64 or not?

[vince1]

Yes I would say it is probably a 64. In 66 (maybe 65) the panhard bar is shorter and attaches to a lug in the center section. The attach brackets on the frame would also be slightly different due to the different angles of the panhard bars.

[vince1]

Although my wife would never let me get away with that, thanks for that idea of clean up in the shower. Maybe I can work something up like that outside to clean up a 66 housing I have.

[Mjminino]

Originally Posted by vince1

Although my wife would never let me get away with that, thanks for that idea of clean up in the shower. Maybe I can work something up like that outside to clean up a 66 housing I have.

That is the spare shower in the basement that never gets used. That was funny

[Mjminino]

What size diameter gears should I be looking for? I unfortunately cant just look for "12 bolt" ring and pinion gears. Does anyone have any recommendations on brand and ratio? I am thinking on 3.42 with 255/70/15's to accommodate my 4L60E

[vince1]

Most common was 3.73. You can figure that out pretty easy now that the cover is off. 3.07 was less common. I've heard that between the two they are a different series like maybe a 3 or a 4 so take a different carrier or spacer or something but other than that my knowledge is almost nil. I would think that a 3.73 gear set would be almost ideal with an overdrive automatic but you are probably quite aware of tire size rpm calculators to get the ratio you are after.

[vince1]

1971 and up? differentials are 5 lug and maybe about 1 1/2" wider (using the shorter panhard bar).

[Mjminino]

Well I am looking at getting THIS.



meant for a 64' housing.

[60-66]

Careful, if that's a 1964 rear it should have coarse spline axles used in 63 64 only. You'll need to replace the entire center section as the pinion is also coarse spline and the side gears.

[Mjminino]

I am replacing everything, using the CPP 30 spline axles, and something along the lines of THIS. (Eaton GM 8.875" 12 bolt Truck Posi + Ring and Pinion 3.73 + Mstr Install Kit)



I still haven't decided on what ratio to go with. using the "RPM Calculators" at http://wallaceracing.com/calc-rpm.php this is the information I have gathered.

(all of these with the 4L60E, 60mph highway speed, 29" tire) a 3.73 will give me 1,815 OD rpm, 3.55 will give me 1,728 OD rpm, 3.42 will give me 1,664 OD rpm, and last a 3.08 will give me a 1,499 OD rpm

The application of this truck is absolutely nothing but a cruiser for the ol' lady and I, maybe take it down the track a couple of times just to see what it runs and launching at red lights , but that is it. Literally a daily driver to take to car shows and go cruising in.

[Mjminino]

So I guess I might have practically answered my own question, does that mean I want/should get the 3.08 gears? I want it to have some get up and go. Heard or read somewhere that the lower gears will mean it is the opposite of that, is that true?

[verdell]

Originally Posted by Mjminino

So I guess I might have practically answered my own question, does that mean I want/should get the 3.08 gears? I want it to have some get up and go. Heard or read somewhere that the lower gears will mean it is the opposite of that, is that true?

I went from a TH350 with 3.73 to a 700r4 with 3.08 and its been ok. It'll still squeal the tires and does great on the highway but i think the way to go is with 3.42's. I'm saving up for a posi and that's gonna put me right where I want to be. Just a thought.

[corvettejim1968]

i have 3:73 with a TH350 and I'm good up till about 75mph. if your doing overdrive 3:73 is the way to go in my opinion. in my 2nd Corvette it came with 3:08 gears and it was a dog in my book. then i did the 3:73 and really brought the car to life.

[60-66]

I have a 3:73 posi behind a 454 TH400 63 short bed and its a blast to drive. If your going long distance an overdrive would be nice but 3:08 in my opinion will kill the go factor

[LVPhotos]

Once again here is a chart to find sweet spot. I run 28" tire, 3.73 gear and .63 od

[NevEno]

I bought the same posi you did from summit. I'm going to be running a 4l60e with 3:73 with a 28 tall tire. We'll see how it works. The rearend you have with that big a$$ panhard bar bracket kills running dual exhaust on the passenger side with the truck lowered.

[Mjminino]

It'll only be a 5"drop in the rear. Using just springs

[61_FL_Apache]

I was waiting to see a funeral notice after your wife killed you for the rearend in the shower..

[Jeff La]

Originally Posted by 61_FL_Apache

I was waiting to see a funeral notice after your wife killed you for the rearend in the shower..

I was kinda thinking the same thing

[Mjminino]

[frankslagoon]

if the backing plates are pressed on it's probably 63. that's probably not good for you if your gona put disks on the rear at some point. I have a small V8 with a overdrive and 3:73 . 28 in tires. if I was running lower tires and buying a third member I'd go for the 3:42

[Captainfab]

Yes that is a '64 12 bolt. It has bolt on backing plates and the panhard bar mount on the passenger side axle tube. I would recommend 3.73 gears with a OD trans. Of course that will also depend some on your engine, how it is built, and what you expect from your truck.

[Mjminino]

You guys are toooo cool!