keeping front end too tight?

[Adger Smith]

You might want to take a look at the converter because the way I'm figuring it it miight have some problems with slippage. Or your numbers could be wrong because the high RPM and high MPH slipage doesn't match the low RPM and low MPH. one way it is about right with 6.5 % the other goes up to about 9%... Something doesn't compute there..
If you go from 4.56 to 4.86 that is a 6% increase in ratio. That would increase your trap RPM 6 % if the MPH stays the same. Say 7100 goes to 7525 and 7400 goes to 7844.
The over all gear in low gear goes from 1.80 X 4.56 = 8.20 to 1.80 X 4.86 = 8.74
The 1.98 X 4.56 = 9.02 overall low gear with no change at the finishline.
That is a 10 % increase in low gear. That is much better than the 6% increase in rear gear change. You might even be able to run a turbo 350 in it. The 3 speed would make it run quicker at mid track, if it hooked.Keep in mind the 350 has a better gear spread and less weight than the T400.