What Gears for a TH350 Trans - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Grumpyroger · 03-04-2011, 07:20 PM

I am a Newbie here, and I have a small dilemma.... I own a 1969 Chev. C-20 equipped with a 350ci engine, I believe a TH350 trans (although the vacuum modulator is located on the right front of trans) and 4.10 rear end gears. It came with 16.5 tires and split rims, but I have changed them to 245/75/16 (30" tall) My problem is trying to figure out which gears would be better suited for Highway use. With the 4.10 gears I turn about 3500 RPM at 65-70 MPH and get real crappy fuel mileage. Any suggestions ?

03-04-2011, 07:20 PM	#1
Grumpyroger Registered User Join Date: Mar 2011 Location: Hesperia, California Posts: 3	What Gears for a TH350 Trans I am a Newbie here, and I have a small dilemma.... I own a 1969 Chev. C-20 equipped with a 350ci engine, I believe a TH350 trans (although the vacuum modulator is located on the right front of trans) and 4.10 rear end gears. It came with 16.5 tires and split rims, but I have changed them to 245/75/16 (30" tall) My problem is trying to figure out which gears would be better suited for Highway use. With the 4.10 gears I turn about 3500 RPM at 65-70 MPH and get real crappy fuel mileage. Any suggestions ?



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