So I've got a non overdrive tranny. Do I change the stump or drop in a 4 speed? Cuz it tops out at about 50

 

drop in a nv 4500 thats what i did and a dana 80 rear end i top out at 105 now

 

go for a 47rh if you wanna stick with the auto or put in a nv4500 or go for the nv5600. it shouldnt be topping out at 50 though. it should be more like 73-75 stock. do some of the free mods and put in a 3200 rpm spring and ull be right up at 90

 

It's got 4:10s in it now

 

i see. well thats probly part of your problem. try swappin it out with 3.54s or something.

 

Is that the highest I can go. Without haven to spool 40 psi before takin off

 

the 727 with "highway gears" were the 3.07's but they no longer manufacture the 3.07's i run about 65 at 2200 rpm. i can scoot about 75 at 2500 on a flat but i dont like holdin the truck that high for hours on end honestly idk if i'd wanna run 105 in one of these sleds hahah i've got 6" of lift and im still trying to restore my handling, kinda hoped new springs id' still have close to factory steering... now i'm up to a custom trac bar, dual sabilizer, adjustable drag link, and sway bar... steering still sucks i'm going to rebuild the kingpins next. like i said idk if i'd wanna do 105. i think an 80 mph highway speed turnin 2100 is ideal but that isnt going to happen with the 727 and 4.10's

 

105 I remember those days

 

if it did do 105 i thank id drop dead. i just wanna go faster than 50 and not burn so much dang fuel

 

anything after 2350 RPM the MPGS go by the way side in the newer rigs 24V and up 2500 seems to be the magic number shoot the 08 6.7L gets 14 at 2450 (70 mph) or 10 at 2550 (76MPH)