Help picking out gear ratio
 

Hey everyone,

I'm about to change out the ring and pinion on my 58 chevy pu and would like to know what you think as far as gearing. I'm thinking 3.73 or 3.90 with 27.5" tall tires and a TH350 trans.

Engine specs,
Chevy 383 all forged XE 274H Cam W 1.6 roller rocker arms
RPM Air Gap intake
Holley 850DP Carb
Vortec Heads 9.3 Comp
120hp shot of NOS

The truck is for fun, no gas milage concerns. Not much freeway use but I don't want to go too extreme with gearing. The engine makes a lot of torque so I'm just not sure exactly where I should be on gearing.

Thanks

3.89 3.73 or 3.55:1 would be fine for 1st gear performance and the 3.55 would have a modicum of relief on the highway. However, thats the easy part, what you really need is a QUALITY converter, with the right stall and proper diameter for the intended application

Anyone else run a similar combo?

that 120 shot is likely adding 200 pounds of torque.that cam is not super high revving so go moderate on the gearing.It will likely eat tires. I use a mild 3.5 gear in my car,the engine revs 6500 and its light weight. 3.9 gears would help you decide to get an O/d trans mission later