rear end interchange?????

[bigunde]

I have that 70 c-20 custom camper and since nobody wants it i guess im gonna keep it and i want a higher(numerically lower) rear end in it.I found a 342 posi thats in a 1987 chevy c-20 but someone is telling me that only 69-70 will fit.Any ideas?

[Green Machine]

If you want lower crusin rpm check out these gears :

http://www.oldchevytrucks.biz/catalog3/0044.html

[68C15]

does anyone make something in the 2.50 range for a 12 bolt? I have a 3.07 right now & did the math. I need to get the rpms down to the caddy's torque band. <hehehehe>

[cadiac]

Caddy? -Thats my thing. 2:50's?? wow -you going nascar? I'm using 3:07's and that 500 loves that ratio, -turns about 2800 at around 75 mph. The truck had 2:73's or 2:93's -? Can't remember what it was now, but my rear view mirrors looked like they were going to fold back when I kept my foot in it. No not really but the speedo went past the 85 top and came wayyy back around to zero again. I pull a trailer now and then so I went for the 3:07's/235 75r 15's. The truck I'm using at present is an 86 Chev 1/2 ton -76 500 a little better than stock/turbo 375 trans. Had almost the same combo. in a 70 1/2. Bottom of the cab had to much rot to patch and i needed a truck in a hurry, -well the 86 had the right price and condition. Miss the 70. will be starting on a 69 3/4 camper special soon.has bad frame -it may become a 72 as the donor frame is 72, -Cadillac of course. I met a guy on a Cadillac forum from Maryland that has put Cad. in several of these trucks. He's modified the firewall to set the cad. futher back. How did you set yours? Guess I got real long winded this am. How about sending me a pic or 2 of your inst? I'll get/dig up some of both of mine. If you are interested, I have a rear from a 75 Olds full size wagon, -is a 2:73 limited slip "Eaton" I'm told. Stout heavy sucker, -should have been under a truck not a car! Not much interest for it. I'll sell it for $50 with extra pair of drums/is in very good condition. Damm -it even came from an aunts car in S. F., S. D. Memeorial weekend I'm going to Des Moines to get a 67 PU, -will then go over to S.F to see family. Could bring that rear with. I also have a 8 1/2" rear from an 80 trans am, 2"56 ratio limited slip /VG cond. -$100- Don't know how the width would be for these trucks? Could get it out and measure it. I've seen conversion kits to put any diff. under these trucks with mount pads and pan hard bars. I'll shut up now # if you want to call, -316-773-2951 or give yours as I have unlimited calling. -Steve

[Vince M]

Bigunde..Do you know what rear you have in the truck. If it's a Eaton (most likely) you don't have any options other than replacing it. I put a 14 bolt into my K20 but it's a bit easier to swap out because of the leaf springs. I had to cut and reweld the spring perches and the shock mounts. Other than that the driveshaft bolted right up and I had to use the E-cables from the original rear. With the coil spring rear you have to deal with the track arm and its mounting to the rear end. Not all rears have this.

[bigunde]

heya vince mine is a custom camper and has the leaf springs.Are they in a different location on the later models?