I am swapping out the rear with a El Camino rear pretty sure it has 3.42 gears in it. Much much lighter setup... That original axle is a beast compared to what I am putting into it.
The 1/2 ton front axle with discs will also help the weight in the front end since the Axle that is on there is just one big piece of metal. They both should be swapped out in the next week.
