As said in an earlier post, rear gearing is application dependent. My current '69 Dart build is going to be a weekend car, not a daily driver. It's based on a 380-horse 360 crate motor that I plan to modify a bit to get over 400hp out of it.
Since it's going to be more 'toy' than anything I'm going with a 4.30 rear gear behind a 200-4R OD trans. I had the trans built as a manual-shift, reverse-pattern with a 2800-rpm lockup converter. Theoretically this combo will give me the best of both worlds. The 4.30 gears will be fun around town and the 0.67 OD will make them behave like 2.88 gears on the freeway. Others here on FABO with a similar lockup 200-4R have stated it almost feels like a 5th gear when lockup hits.
Other deciding factors for the 200-4R were that it fits in an A-body tunnel without major tunnel surgery and there is no computer involved with the transmission. Since mine was built as a manual-shift, I don't need to worry about a throttle valve cable or adjustment.
