The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

piecesparts · 02-11-2009, 09:16 PM

The common breakover point between series 3 and series 4 carriers is around the 3.42 range. For everyday operation the 3.42 is very common, however the acceleration of a 3.73 gear is really nice and you can drive it comfrotably. Mine has done several Hot Rod Power cruises, with no problems.

My Daily driver is a 91 Silverado with a 3.42 gear and a 5.7 engine and 700R4 setup. The TBI is getting me around 20 MPG daily. However that is with a lot lighter truck than the mid 80s were.

02-11-2009, 09:16 PM	#8
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: 12 bolt rear end question The common breakover point between series 3 and series 4 carriers is around the 3.42 range. For everyday operation the 3.42 is very common, however the acceleration of a 3.73 gear is really nice and you can drive it comfrotably. Mine has done several Hot Rod Power cruises, with no problems. My Daily driver is a 91 Silverado with a 3.42 gear and a 5.7 engine and 700R4 setup. The TBI is getting me around 20 MPG daily. However that is with a lot lighter truck than the mid 80s were.