LD85

I had planned on changing my 3.07 rear gears to 3.54's, but my dad, and old time racer says, go to 3:73's cause you wont notice that much of a difference.

What will my RPM be at 70 MPH, interstate speed?

Currently with my 4+3 in OD I run @ 2000RPM @ 70 MPH.

I know there are some calculaotrs out there on the web but I have yet to find them

CFI-EFI

I did some quick figuring for you. I don't know your OD ratio, so I used the .70:1 of the 700R4. With a 26.0" tire and 3.07 gears, 2000 rpms is 72 mph. Same set up with 3.54s, 2000 rpms is 62 mph. 70 mph takes 2250 rpms. With 3.73s, 2000 rpms gets you 59 mph. 74 mph takes 2500 rpms. I know the OD ratio is off, and the tire size probably is too, but this will give you a basis to look from. Another consideration is your trap speed in the 1/4. Good luck, and...

RACE ON!!!

Caboboy

Larry, here's a calculator I use. My 3.07s also put me at around 2K @70 MPH with either the Z06 or the ZR1 wheels I have. I kinda wonder about 3.73s with all that torque down low........

http://www.dalesplace.com/htm/inform...calculator.htm

LD85

Thanks for hte calculator,, regarding torque, I wonder too but with SKI doing what he is doing torque wise, I can see how this would be worse.

I will dyno the car in the next 2-3 weeks though and I will decide for sure then

OD
2:88 - 1.93
1.91 - 1.28
1.33 - .89
1.0 - .67

Using the #'s above it would be 2289-RPM @ 70 MPH using 3:73's
Using the #'s above it would be 1884-RPM @ 70 MPH using 3:07's

The 3:07 amount seems low compared to what I remember, but I can check it out this weekend while I AM "tooling about"!



[Modified by ld85, 12:19 PM 3/2/2004]