LFOTremolo

77 original L82 (replaced with a ZZ4) 4 speed BW Super T10 Car. How can I tell what my rear gear ratio is?

sullyman56

You can either go by the code stamped on the differential housing or jack up the rear, rotate the rear tire one full rotation while counting the number of times the driveshaft turns. A piece of tape or dab of touch up paint on the drive shaft near the rear u-joint will give you a good reference point.

C3w4sp

Car on jack stands, put a mark on the driveshaft, tranny in neutral, observe how many revolutions the drive shaft makes with one revolution of the rear wheel. For example, If it goes around 3 1/2 times, you likely have a 3.55 rear gear.

C3w4sp

Sullyman types fast!

LFOTremolo

Thanks, fellas--something fun for the garage time till the rain lets up--have a great weekend!

c3_dk

Looks like a nice ride !! : -)
Enjoy our 77 :- ))

revitup

If it's 1 '77 L-82 and the original rear it's most likely 3:70.

cor28vettes

http://forums.corvetteforum.com/show....php?t=2401680

I had a 62 Bel Air bubble top in which I went from stock whatever to a 4:11. They changed the ring and pinion on it. Therefore, trust but verify any housing codes.

Back in the day 4:11 and 4:56 rear ratios were very popular on Chevrolet. Many mods were done inside that housing during the 60's. Less so in the 70's with changing times.

Far as stock...out of 49K produced in '77 only 972 had the G95 optional rear axle ratio which cost all of $14.

www.crawlpedia.com/gear_tooth_calculator.htm

Grumpy 427

What tire size is on the car, and what rpm is 60 MPH. I have 255/60/15 on mine with 3.55 gears. 60 mph is 3000 rpm, 100 mph is 4500. I picked up 500 rpm when i switched from 3.08 gears. car is way more enjoyable to drive with this gear ratio in it.

C3 4ME

I was going to mention the same as was posted above. If it's still stock, it should be a 3.70 gear ratio.

LFOTremolo

Haven't gotten underneath her to check the shaft spins yet, but I know that I turn 3000 at 70... Tires are 225 70R15's...