Well I got the new chunk for my 9" rear end and got em swapped out while I was at work today.
Previous gear was thought to be a 4;56 but turned out to be either a 4:63 Richmond gear set with a 37 tooth ring and an 8 tooth pinion or a 4.11 with the 37 tooth ring and 9 gear pinion.
Turning the yoke and counting has me fairly certain it was the 4.11 but either way my rpm's at 70 dropped from 4000 down to 3200.
I gave up some bottom end power, but the overall change in the car was very pleasant. It is quieter, runs a bit cooler and doesn't require quite as much shifting to stay on the power band.
My speedometer was 10%+ fast before and is now about 5% slow until I can get the proper speedometer gear in, but that is manageable as it still keeps me within the range of most officer's general leeway if I am not blatantly violating the law.
Now I have to decide if keeping the spare chunk is worthwhile. Gears and bearings all look excellent and it is a "N" marked case which I suppose means nodular. 28 spline and track lok with Richmond brand gears. I let my mechanic change it out and he did not transfer the pinion snubber over, so it looks like I am going to have to crawl under the car at some point to correct this.
I hate working under cars! I would have changed the rearend myself, but Larry is a friend and has a lift and a shop and rarely charges me more than just a token amount. Besides he sold my Volvo for me yesterday for far more than I was expecting (an extra grand) so I thought throwing business his way was just the right thing to do.
I could actually go on a roadtrip now!