found something cool under my truck today

[71chevylowrider]

First off, the truck was built by the PO over a 20 year period, so I'm slowy finding out what all has actually been done to it.

I pulled the diff cover & wanted to see what gears I had in my 12 bolt today, unfortunately it's not a posi as I was hoping (some burnouts left 2 marks) anyway, I found it had markings that calculate to 3.73 gears, the rear ratio calculation chart that i've been using shows it shoud be 4.56 gears according to transmission,tires size, rpm's & speed (TH-350, 27" 3,500 rpm's, & 60MPH) but I was pleasantly surprised when i got a look at my nice custom made aluminum drivshaft, I love it when I keep finding cool stuff on my truck. Now I gotta figure out why my RPM's are so high at 60MPH.