318 power?

3.55s are plenty of gear for an automatic, behind a torquey teener.
You would hate 4.56s within a few short hours.
But I assume you were kidding!

With 23.4s and the current 2.76s; your hiway Rs works out to 2973@75,locked up. At 75 the TC will very likely be locked up.For me this would be unacceptable. I would be trying to fit some 28.0s in the back, to bring the Rs down to 2485locked up.Even that is buzzy for me. But here in Manitoba the speed-limit is mostly 100kph, which is 62 mph. For me that would be 62@2054 and totally acceptable.And so that's what I got!A final drive of 2.769. And 3.55s out back; hooray for overdrive!