jophuss36

iTrader: (1)

Ok so I can't decide what gears to go with. I'm in the middle of my 80e swap now and am scared about my power loss off of the line with the taller 1st gear. I run 33x12 inch tire half the time and a31.5x10.5 the other half. I'm not worried about gas milage, but want a better quartermile time, and want to be able to cruise down the highway at 80 mph without running 4 grand lol

1Bear

iTrader: (1)

The highway rpm at 80mph will still be a little rough either way, but there is not that much difference between the two to scare you away from either one.

2937rpm at 80mph with the 31.5" tires and 4.56 gears
2800rpm at 80mph with the 33" tires and 4.56 gears
3110rpm at 80mph with the 31.5" tires and 4.88 gears
3000rpm at 80mph with the 33" tires and 4.88 gears

Hell, I'm turning about 2700rpm at 80mph with 4.56's and a 4L65, so I really try to run about 65 to 70mph so that my rpm's will stay about somewhere between 2200 to 2300rpm and change.

jophuss36

iTrader: (1)

Yaw ibwas looking at those calculators, it's just hard to tell if it will be liveable or not.... I really wish the 4l80e had the lower first gear..... I wonder how much I would bennifit in the quarter with 488 gears as oposed to 456? Would it be worth the high rpm on the highway?

Atomic

iTrader: (42)

go with the 4.56s

TXsilverado

iTrader: (19)

where do you make power? dyno sheet?

jophuss36

iTrader: (1)

https://www.performancetrucks.net/fo...=463591&page=2. There's a link to it

jophuss36

iTrader: (1)

Here's where I'm at, right now my trap speed is 102. With the456 gears il be at 121 at 6 grand with the 31s and 488 will be at 113mph at 6 grand. If I ended up getting a turbo or Procharger down the road with drag slicks to launch in 2wd. Will I be geared too low with the 488? That's the only thing stopping me right now

dlt76028

iTrader: (13)

I'd do the 4.56s. You would be over that 113 if you added FI.

skeet

iTrader: (18)

456 = 102 trap speed? whats the rpm? 6k? if thats the case with 488s you may trap 104 and rpms would probably be around 62-6300 crossing the traps.

Atomic

iTrader: (42)

I have 4.56s and its too much gear for my blower and 35s