The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1972 GMC 3/4 TON 4X4 BIG BLOCK 4 SPEED (Craigslist)

**Bob B.** · 02-23-2010, 12:43 AM

There were a number of reasons GM didn't install Big Blocks in 4X4's until 1981. The Big Block was to heavy and made too much torque for the Dana 44 front axle and transfer case, the only automatic transmission used in 4X4's was the Turbo 350, and there were probably clearance issues as well. It is interesting that Ford didn't use 460's in their 4X4's until the 1980's as well.

02-23-2010, 12:43 AM	#12
Bob B. Senior Member Join Date: Aug 2005 Location: Los Angeles Posts: 1,306	Re: 1972 GMC 3/4 TON 4X4 BIG BLOCK 4 SPEED (Craigslist) There were a number of reasons GM didn't install Big Blocks in 4X4's until 1981. The Big Block was to heavy and made too much torque for the Dana 44 front axle and transfer case, the only automatic transmission used in 4X4's was the Turbo 350, and there were probably clearance issues as well. It is interesting that Ford didn't use 460's in their 4X4's until the 1980's as well. __________________ 1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90.