[MrChevyDC3]

Good day, Good day.
Dre' with the '80 Mali is here again, with a question for you all. First off, a general question. How much difference does a clean rear end with fresh fluid make if your rear end is old and dirty and hasn't been changed in about a decade? I just changed my rear end "dope", and when I took the cover off, it was thick, gooey and quite foamy to my surprise. A little info on the car- I found the body in a junkyard and put in a souped-up 350 sbc and a th400 trans with a shift kit and a 3000 stall convertor. I'm sure this is the stock rear end (I don't have Posi) and the stock gears (any clue to the ratio?) and it looks like it hasn't been changed since the car was made back in the day *l* But where did the foam come from? I wanted to take a pic and post it for you guys. And will a 12 bolt rear end (I have a ten bolt) Help out my performance?

[DoubleVision]

A different rear isn`t going to help any power wise, the only thing that will would be a different set of gears, you can read the ratio by looking on the ring gear, it`ll look something like this: 41 11 divide 41 by 11 = 3.73:1
Foam occurs after the lube has so many miles on it that it`s broken down completely and is just as thin as motor oil, it can also be caused by condensation so you may want to check your vent. I would just refill the diff with Royal Purple gear lube, it cuts rolling resistance and is a far better lube than standard lube.

[94lt19c1]

Actually according to this http://www.chevyhiperformance.com/te...les/0304_nine/, the 12 bolt uses less power than a 9 inch ford, who knows compared to your ten bolt.