First off you would be advised to swap the input shaft and pump so it can utilize the later 67 and up converter. The stock low roller (sprag) works fine. The only upgrade low roller would be the A&A, TCI, etc $200 unit. The others are for case repair. Its not the outer race that fails, it the locating tabs that bend. The more expensive unit has more rollers. I've successfully run the stock 65 low roller in 9.0, 10.0,and 11.0 cars, many runs, no failures. If your worried about the high gear drum exploding it can be upgraded to billet but they're pretty expensive. I personally have never broke a stock one. Note when upgrading the pump; if the front clutch drum is a 3 clutch get a 4 clutch drum and upgrade to the 71 and up pump, input and drum. Kolene steels are nice but not really necessary. Borg Warner tans do an excellent job. CRT,A&A, or Turbo Action manual valve body. Red hard band, 3.8,4.2, or 5.0 lever, 2 springs (inner and outer) in the front servo, .050"-.060" front clutch clearance. I've built many with this formula. Will easily run 10 second ET's with nothing but a yearly fluid and filter change. All stock components can be used.
Doug