You should be able to launch better with the 4.10's, but you'll like it more up top with the 3.73's. If you match the combo of cam/heads, torque converter, and gears, I think you'll be happier. If it were me, and I already had 4.10's, I'd upgrade the camshaft to something that would work with about a 3k converter, if there's PCM software available that could support those mods (not sure what's available for the SBC Vortec's). As a comparison, I used to have a 71 Camaro with a 350, DartII heads, Comp 292 Magnum cam, 3k converter, and 4.10's, and I felt that the combo was perfect. It launched like a beast, and I had it at 6800 rpm in 3rd gear and it was still pulling when I ran out of road. I had the car and drove it when I was 17-19 years old and never got it to the track unfortunately, but I was very happy with the combo. I know you can't compare a car and a truck, but hopefully this info helps a little bit.

 

**** my 3:42 to 4:10 swap made a pretty big differance for my truck.. maybe cuz its a reg cab and lighter then most of yalls ext cabs. n for me the costum tune was the biggest difference not the gear

 

Umm, right. I'd love to know where you heard that.