RPM at MPH

[409gang]

When i had to replace the 3:55 gears in my Vette i really wish i had gone to 3:36s Went to Buc-ees yesterday and got 10 gals. of 91 EO Plus at 3.27 a gal. for the Vette and then topped of the Dodge with deisel at 2.79 The EO Plus even smells like real gas!!!

EO, ethanol out?

 

[Barry Taylor]

EO, ethanol out?

Thats what they call it on the pump. Pump handle covers are blue!

 

[Seon]

Curiosity got me about the gear ratio so put the Bel Air on the lift and based on the numbers AB120 5, the 3rd member is 3.36 but based on calculations using 26" tires and 3000 rpm at 60mph, the ratio is 3.90.



Muncie code 3925660 is '68-'70 with 1" bore but does identify if it's close or wide ratio.

 

[MRHP]

Tach is probably not accurate, so calculations are off.

 

[Don Jacks]

I came up with 2605 at 60 when using a 26 in.tire and a 3.36 gear.

 

[Seon]

Short of taking the pumkin out and counting, I think I'll stick on what I have and call it a day.

 

[blkblk63ss]

Mark the wheel and the drive shaft with chalk or masking tape. Turn the wheel TWO revolutions and count the number of driveshaft turns. The number of driveshaft rotations will help you determine your rear axle ratio. For example, if it turned 3 and a half times, it's a 3.50:1 ratio.

 

[blkblk63ss]

Block one wheel ifyou have a non posi. If posi you can let both wheels off ground counting tire revolutions