[decooney]

With the torque in a stong FE, you'll do better overall with the 3.31 rear gearset - it just pulls through first gear and its nice to have a little extra in 4th gear. Most people I know that had 3.54s/FE combo are much happier with 3.31s now. My former car had the 3.08 differential and an FE, and overall I feel the 3.31s are about right, and particularly with the wide-ratio trans Toploader or custom big-Toploader with wide ratio setup. Other friends with SPFs running the rear 3.73 gears have changed to 3.27s and like that much better, but for those running the .68 overdrive they say its a tad too tall if you are running a larger cam.

I'm considering (waffling about) a 5-speed road race trans myself but sure do like the way the Toploader / 3.31 setup runs with a larger camshaft for everything except long highway trips. That .82 5th gear would be nice; which drops from 3,000 rpm higway cruising to 2,450rpms. As others have noted, you need to provide your cam/motors specs too to get a better idea from us.