if i swap my 3.55 gears to 4.10s, will it effect my rpm(hwy). i'm going to swap to a518 with 4.10s. is this the same as 727 w/3.55s in regards to hwy driving? which 1 gets better mileage?  

well the 727 and the 518 both have a 1:1 ration in 3rd gear the 518 has (i think) around .69:1 4th gear. id say if your gonna use it as a highway machine id go with a little higher maybe 3.90 i have a dakota with 3.90 with an a518 and it even rolls out the rpms at highway speeds  

i guess  4.10s is too much. hmmm. i guess 3.90s should be fine eh?