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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Rear Drivelines, Drive Axles and Gearing => Topic started by: Bigrig on July 20, 2017, 10:39:44 PM

Title: 3:73 Gears ok street and strip ?
Post by: Bigrig on July 20, 2017, 10:39:44 PM
Building 86 chevy 2wd longbed with an Fully built Olds 455 roller rocker, aluminum heads, aluminum intake, long tube headers , holly demon 750 cfm carb and a Turbo 400 stage 3 shift kit and 3000 stall.  stock 15" wheels .  3:73 gears .  The truck is not put together yet and I am wondering if the 3:73 are going to be ok for short road trips and freeway driving without wrapping up the RPM's too high ?  Anyone else have a similar set up or advice
Title: Re: 3:73 Gears ok street and strip ?
Post by: Rattler12 on July 21, 2017, 08:13:25 AM
I've got 3:73's in my 83 but they're behind a NV 4500 5 spd manual trans with .73 OD. The combo works out well. With the 400 and it's 1:1 final ratio you're going to be 33% higher in the rev range at hwy speeds with street tires. While my 454 is cruising at around 1950 rpm your 455 will be at 2650 or so. You'll need deeper wallet and a bigger gas tank.......:)
Title: Re: 3:73 Gears ok street and strip ?
Post by: Irish_Alley on July 26, 2017, 08:29:37 AM
rattler, not to hijack or anything but whats your MPGs?

Title: Re: 3:73 Gears ok street and strip ?
Post by: SkinnyG on July 26, 2017, 10:49:29 AM
I went from 3.07 to 3.73 on my daily-driver C10, and I'm running about 3000rpm at 60mph or so.  I noticed a teeny improvement in fuel economy and my guess is because 1) the cam is at a happier rpm and 2) I'm now cruising above the torque converter's stall speed.
Title: Re: 3:73 Gears ok street and strip ?
Post by: Rattler12 on July 26, 2017, 12:53:45 PM
rattler, not to hijack or anything but whats your MPGs?
10 mpg no matter what..... :'(
Title: Re: 3:73 Gears ok street and strip ?
Post by: Irish_Alley on July 26, 2017, 12:59:33 PM
is that before the nv4500?
Title: Re: 3:73 Gears ok street and strip ?
Post by: Rattler12 on July 26, 2017, 09:14:50 PM
is that before the nv4500?
After......but it runs like a scalded dog......so there's that
Title: Re: 3:73 Gears ok street and strip ?
Post by: Irish_Alley on July 26, 2017, 10:05:38 PM
I know my 91 v3500 crew cab with a 350 got 12 with the 4l80e and 4.10  Now she can get 16 with the Cummins  ;)