Need driveline help tired 350/350/4.11

[mattfrediani]

So I have a tired 290hp 1970 sbc 350 with a good rebuilt T350 and 411 gears in my K20.
I have to use the truck on the freeway some times and it scares the crap out of me. The motor is teaching at about 2800RPM with my 33" tires doing 60mph.
I need to be able to use this truck on the freeway sometimes and dont want to install a new tranny and gears. I also live up a pretty decent hill.

I was thinking to go with 3.55 or 3.07 gears? this truck is not going to pull trailers or do work besides go to the dumps. will the 3.55 or 3.07s work for me? will I be able to make it up my hill with out damaging anything? I know I need a better tranny but I have money issues and have spent so much already. I just dont know what to do??

Thanks
M

[trac209]

I run 3.07 gears in mine,no complaints.

[Ironangel]

In a four wheel drive your committed to changing both gear sets. Or get a late model 4-speed tranny with a controller and drive shafts...$2K if your lucky...These trucks were never meant to run 75 down the highway like these late model roller motors with 4-speed transmissions. "Old school aint cheap, just didn't cost as much back in the day"

[suburban99]

My 1972 K10 LS swap runs at 2300 rpm at 70MPH with 35" tires...maybe get taller rubber?

[special-K]

My '72 K2500 with same powertrain runs more like 2500 rpm at 60 mph and that is no problem at all. That's what the truck was made to do. Since you have an 8-lug truck you won't be finding any 3.08 rear gears and 3.73 isn't worth the cost and effort for such a minimal change.