My 258mm (10ish") CircleD was built to foot brake to 3500 RPM, and I'm guessing it'll flash a hair higher, a single disk will still give you a positive lock-up capability, but not quite the durability of a multi disk setup. I chose single disk due to my very unabusive settings for lockup, some prefer it other ways. That's why there's so many different ones built

 

I've had no experience with anything but PI. Two of them now. Went with them again on the 80e because I had no issues with the one from the 60e's. I love how the 3 disc clutches lock up. Feels like another gear shift.

 

I put in a pi 3000 5 disk lock up launches great but a little loose for daily driving might send it back to re stall to 2800 i got the one for the 4l80 swap so you dont have to change the flex plate. talk to jack.

 

It's odd with the stock converter that you are only cutting a 1.9 60'. The stock converter with your setup even without the nitrous should be flash stalling to 2600rpm or higher and with the torque from your MP122 down there you should have a 1.7 range for 60' time. What tire are you running? How much timing do you have in it down low? Just a few curious questions. You should really be running very strong even with the stock converter and only having a 3.73 gear.

 

Tires are 12.8" wide and 28" tall. ET Streets. Not sure of the timing. Truck runs mid 12's at 109mph in warm muggy air. Haven't figgered the nitrous out yet. Trying to get everything sorted out without the gas first. I'm not sure what the stock converter flashes to. Truck leaves with little or no tire spin. Just thought it would leave quicker with a little higher stall.