The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 47-55.1 1951 GMC Floor High Hump

dsraven · 03-10-2023, 10:20 AM

if you're installing the 292 and the 4 spd from the same donor truck, '64, then it will likely have the granny low gear. most guys simply start in 2nd with those unless they have a load. possibly you could find a newer trans with better ratios or even an overdrive to help with rpm's on the highway. be mindfull of the rear axle ratio and the trans ratios with the 6 cyl engine. I guess it would be just like driving the '64 as far as highway speeds and power are concerned. lots of those guys are looking to upgrade to a 5 spd. it depends on what you want.
you probably know this already but in case you don't, the installation of an open driveline in place of the old torque tube will require an adapter at the axle to spring mount because the torque tube axles had a pivot on the spring mount and weren't mounted directly on the center of the axle tube like the open drivelines are. they sell those adapters at some of the suppiers. some guys make their own using spring pads from a trailer axle supply place.

03-10-2023, 10:20 AM	#7
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 7,903	Re: 1951 GMC Floor High Hump if you're installing the 292 and the 4 spd from the same donor truck, '64, then it will likely have the granny low gear. most guys simply start in 2nd with those unless they have a load. possibly you could find a newer trans with better ratios or even an overdrive to help with rpm's on the highway. be mindfull of the rear axle ratio and the trans ratios with the 6 cyl engine. I guess it would be just like driving the '64 as far as highway speeds and power are concerned. lots of those guys are looking to upgrade to a 5 spd. it depends on what you want. you probably know this already but in case you don't, the installation of an open driveline in place of the old torque tube will require an adapter at the axle to spring mount because the torque tube axles had a pivot on the spring mount and weren't mounted directly on the center of the axle tube like the open drivelines are. they sell those adapters at some of the suppiers. some guys make their own using spring pads from a trailer axle supply place.