I kept the 3.90 gears in my suburban and installed a SM319 3 speed overdrive. I easily run 70-75 with it powered by a stock 248. I have power front discs also, which I would recommend.


"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.