[Anthony]

The tremec TKO600 has the same gear ratio's as a wide ratio toploader, but an added overdrive.

With the 2.78 first, you can run a 3.07 rear (what I would recommend with a WR toploader), and have a respectable start-out, and have some cruising benefits.

With the TKO600, you can run the 3.54 rear, and still have a respectable cruising with the OD gear, or you can choose to run a 3.31 to 3.07 rear as well.

With a CR toploder, you pretty much run a 3.54 rear, maybe a 3.77. The gear spread is closer spaced, what I like better, and I don;t use it as a daily driver, so cruising in 4th is tolerable, as all of the muscle cars were back in the sixties. Most ran 3.55, 3.54, 3.73, or something like that, without OD, and using 14" tires. You don't necessarily need an OD, but it's nice. I'll keep my CR toploader.