question for those who actually swapped in a v8

im getting ready to swap in one of the two driveline i have a 350/th400 and a 360/727 both trannys are 3 spds i heard i will have to swap my rear end because it has 3.90 gears is this true? i have a 12 bolt out of a chevy truck i can have narrowed but my question is how does the truck do on the highway like 65 75 mph is it screaming? also if i do have the 12 bolt narrowed and have the stock axles narrowed also and re-splined how much should this cost? dont want to do it if i dont have to thats just more money i could sink into the motor and tranny thanks hope all this is clear

mine has a c4 trans and i would not want too drive a long trip,i have only driven it a few mile. get a OD trans thats your best bet.

if you are gonna throw a 350 in there and you want to drive on the highway, get a 700r4. or you can get a 4l60e (what i have) if you want an electronic transmission. if you are going with a carb'd motor, then you have to buy a tranny controller (mine was $1200). best bet is to stick with a 700r4.