What gear ratio should I run? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

OrangeCrush1970 · 12-09-2007, 01:04 PM

Currently, I have a TH350 running to 4.10 gears in my 12-bolt rear end with 265 / 75r15's (30" tires). I have read that a safe operating RPM range at highway speeds for a small block is between 1800-2800 RPM’s…Im up around 3000 to 3500+ RPM’s. This is my daily driver and I just don’t want to beat my 350 to death. I would also LOVE to see some better mpg’s. Can anyone suggest the best gears to run in our trucks? 3.73’s or 3.55’s? I’m not towing anything, not doing any off roading and my truck is not working on the farm anymore.
Thanks guys-

12-09-2007, 01:04 PM	#1
OrangeCrush1970 Registered User Join Date: Jun 2007 Location: Smyrna, GA Posts: 709	What gear ratio should I run? Currently, I have a TH350 running to 4.10 gears in my 12-bolt rear end with 265 / 75r15's (30" tires). I have read that a safe operating RPM range at highway speeds for a small block is between 1800-2800 RPM’s…Im up around 3000 to 3500+ RPM’s. This is my daily driver and I just don’t want to beat my 350 to death. I would also LOVE to see some better mpg’s. Can anyone suggest the best gears to run in our trucks? 3.73’s or 3.55’s? I’m not towing anything, not doing any off roading and my truck is not working on the farm anymore. Thanks guys- __________________ *Rottenwood Garage* 1970...71...72 C1500 aka Orange aka Sideshow Bob 540 BB Straub Roller Cam, AFR Magnums, XP 950, TKO 600 2 Tons of Fun Last edited by OrangeCrush1970; 12-09-2007 at 01:06 PM.

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