there was a posi for the TF rear, but you're not likely to find one - the stock rear can take lifting the front wheels off the ground on my buddies 55 w/ a built 427, and 3.55 gears are available for it
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics
