[Stan Weiss]

Originally Posted by Mike S

Racing season is done here in the north east, I am flirting with the idea of going from a 4.10 to a 3.90. Right now I am running a 4.10 with a 30" radial and crossing the line at 6600 at 133 with 7% convertor slip. The car is cutting 1.31 60's. Right now I have an 850 Holley and 340lbs to try and slow it up for 10.0 index. Saturday I ran it all out and ran 9.94. I want to gear it for 142 or so at 6600rpms.
What effect will I gear change have on the convertor and launch? I am worried it will make the convertor less efficient. Will my 60's suffer?
Want to take the 340lbs out and put the 1050 holley back on it to see how close I can get to 9.5's.

Changing the rear gear should increase the convertor slippage. A 3.73:1 with 10% slippage should get you 142 MPH @ 6600 engine RPM.

Stan