[jim_howard_pdx]

Jeff said it all,

The C-4 is a 50 year old design. The FMX transmission was a much stronger unit and found its way behind the Clevelands in the early 70's. The AOD is built around the FMX set up.

C-4's are basically ok if built for full race. But the LenTech is fully modern, will support a good 300-400 more horsepower, and they offer the advantage of the 4th gear. It is possible, with a 4.86 gear and 4,500 rpm stall converter to run as a 4 speed. I do not recommend this for a street or highway driven car, but you could expect to drop nearly a half second on your ets with this combination.

Jeff, what rear end gear are you running?

I love your 121 mph times there Jeff. You must be pushing near 500 hp!!! I was 136 to 138 at 9.2 but ran 4.57 gears with a C-6 and the Tallest slicks I could run at the time.