how can you identify the rear gear ratio on a 85 truck? Its factory with a 4.3 V6 and 400 turbo tranny. Yes its origional, I have 1/2 the factory window sheet as well as the origional glove box option list that shows its factory. Is there a code for this to look for? I am planning on swaping the 4.3 for a Goodwrench 350 and want to be sure its got good low end while maintaining reasonable mileage.
There is a code stamped on the axle tubes next to the housing.It could be on the right or left side.The only way to be sure is to take the cover off and count the ring gear and pinion.Then divide the number on the ring gear by the number on the pinion.That will give the ratio. Craig Hager tech1@chevyduty.com
