There is the Old School Street Twin "Original" that uses a B&B design pressure plate. That thing is a monster, good to over 1200hp or something like that.

McLeod had developed a softer version of that. Still a twin clutch, but smaller diameter, can use stock flywheel, and is a diaphram pressure plate with a super low 1800lbs!...compared to a Centerforce DF of around 3400lbs. These are the RST and RXT street twins. RST is all organic disc and good to 800hp and the RXT has dual friction material and is good to 1000hp. Both are diaphram and super low pedal pressure. They are supposed to hold like mad, but super nice engagement,....very smooth!!!! I hope my RST doesn't break stuff.

I just looked it up. Is it # 6913-05? It says for 140 tooth flywheel and 800 hp. Jegs $719.

Can't recall,...look up their website, but mine is #6913-02 is the 23 spline unit for 130 tooth flywheel.

I spoke to their tech line the other day, because my disks fit pretty loose on the input shaft. The tech person is the guy that designed this clutch. He said it's fine and is supposed to be very loose to give great disengagement features, and not to worry. He has the same clutch in his 57 chevy with big hp, and he can push this clutch in with his hand very easily, no effort. He also said it doesn't have the ON / OFF feature. It is a great STREET clutch that can take the hp at the track. It's not a RACE clutch.