I had a T56 behind my LT1 (~500rwhp) and it was eating clutches. I even went with a SPEC Stage 3 that lasted a month. I was drag racing a little with MT 28" slicks. Got sick of that and went with a TH400 for the last couple of years. Now I'm not going to the track so much and would like to go back to the T56 to make it more streetable. I've read about the McCleod duals, SPEC 3+ and 4's, but what have people used in real life that works and lives?

 

McLeod Street Twin

 

McLeod Street Twin with steel flywheel. 5,000-6,000 RPM dumps on sticky full slicks on a well prepped track. I actually bought it used from a buddy w/ a 900+ HP 30th SS convertible, running 9.0 @ 156, 1.30 60-ft. I ran it for a few years, then sold it used once again to a guy in TX as part of a T56 conversion.

You will find that as you approach 1,000 HP, the Street Twin will last longer than a stock T56. That's when the TH400 becomes attractive.

 

anything around 1k RWHP and 6k RPM clutch dumps will stress, if not kill, clutches and everything downstream of it

with that said a "dual disc" clutch offers twice the friction surface over a single disc clutch. The Street Twin has organic clutch discs which drive like stock but hold well.

McLeod can make a ceramic puc type disc also for it if you are more drag use vs street....but street manners are never as good with aggressive friction composite discs. It is always a trade off.

I make nowhere near 1k RWHP but I have the McLeod twin and wish I had just gone with it sooner vs several brands of single disc clutches using various friction materials for discs

 

I was launching on straight motor.... only 500 HP. Spray didn't hit until 60-ft out. With the TH400 it's actually possible, if not a bit scary, to launch on the spray.

 

The Street Twin is rated for 1200hp. I have its little brother, the RST (rated for 800hp), on my LS1 car. I don't have a ton of power (yet), but the pedal effort is identical to stock, the engagement is smoother, and it's holding power is noticeably better. It costs a bit less than the Street Twin, too.

I paired mine with an ACT billet steel flywheel, which weighs about half of what the stocker does. Not great for drag racing, but awesome for street driving and autocross/road racing.

 

You won't find anything better than a McLeod...we've been using them for decades, back when it was Weber.