Hi all, please help me decide between a McLeod 75357 Street Extreme or Spec SC663H? Is there any reason to pay ~$100 more for the Spec?

This will be fitting on to a Spec SC57A LS1/6 style flywheel which I’ve already purchased for my soon to be modded L92 and mated to an Fbody T56.

Or is there another brand of clutch that I should be considering?

 

For a single clutch look at the Diamond from Texas Drivetrain Performance.

 

I have a Diamond stage 3 that’s been balanced. I put 40 miles on it and it didn’t like my 750hp 434, so I went RPS BC2. I sent the clutch back to TDP and It’s got a new lightweight billet steel flywheel. Been on the shelf for a few years now…hit me up if interested.

 

Do the Diamond “stage” clutches fit an LS1/6 flywheel, or do you have to use their own flywheel?

 

Do you mean the Centerforce dual friction? Just googled it and that’s double the price of either the Spec or the McLeod. A bit out of my price range to be honest.

Is it really twice as good?

 

They come with their own billet steel flywheel.

 

Disk Inertia can damage/wear out the Syncro Rings.
A high weight disk will cause SLOW SHIFTS.

 

^^^ This ^^^

Probably at least 90% of the total effort the synchros have to do to equalize the speed of everything, is to speed up / slow down the clutch disc. It's HEAVY, and even worse, it's YYYUUUUUUUUUJJJJJJJE. All of its weight is out 4 - 6" from the centerline, as opposed to transmission parts that are mostly within the near 1 to 1˝" or so. Meaning, EVERY OUNCE of disc weight, has around 4 TIMES AS MUCH leverage on the synchro rings, as the transmission does.

A dual-disc clutch just adds to that. At some point there's a tradeoff between the extra grip, vs the extra weight; not sure where that is in all cases, butt it's something that should be considered.