Installed a tremec tko 500 in my 67 Cougar a week or so back, and it has been a huge improvement. Now I'm cruising at roughly 1500 rpm versus 2500 before, and for the first time in years I went on the highway, at roughly 2000 versus 3000 before. The overdrive and sharper shifting is awesome. Had a Ford toploader, wide ratio, for many years before. Kept my factory cast iron (truck) bell housing along with the clutch and pressure plate, none of which was touched during the switchout. Got it with the classic Hurst shifter handle, which is too tall in my opinion - I'll be getting one roughly 2" shorter. Overall it was quick and easy to change out. Hardest part was dealing with the "donut" tremec puts on the tail shaft - I wish they wouldn't have.