i am puting a 355 with a modified TPI and a 700r4 with 2000-2200 stall in a 68 chevy truck and i am trying to decide what gear ratio to run. i have seen posts on here stating 3.42 is good gear ratio for camaro with TPI but a truck is a little heavier and the tires are 27" tall. how does the extra wieght and larger tires effect gear ratio and engine speed?

 

3.73 may be great for your combo. It made a huge difference with my 3400# Formula going from 3.23's and it wasn't too bad on the highway as either. with your taller tires, it will keep the rpms down a little at speed.