Howdy,

The 742 power lock sure grip unit in my 68 GTS is starting to drive one tire more than the other. There seems to be two clutch pack sets available for the 742. One has thin shims and the other is said to more aggressive.

Can I get some insight on which to use? Car is 3650 with driver, 475hp with a face plated a833. Also installed a Big Shot NOS plate and Doug's cut outs. : D All of that is kept in check by a NOS mini progressive and a Clutch Tamer.

Trying to spin the tires at the hit until we can get the Dana 60 finished. Not difficult with 235/60/14 m and h muscle car bias plys. FWIW car has QA1 stocker star R's front and rear.

Thanks for any insight!

The sure grip units are interchangeable from all the cases. 741/742/489. Carrier bearings are different from open to sure grip unit. Your underlying question, I would go aggressive. Doesn’t sound like a moderate combo.

Well I've used both and the thin pack will do just fine. The thick pack will more or less be like a spool .

Gus

Second this. We installed the thick one and it acts like a spool. Maybe that's what you want

I wonder if that thick pack is the clutches for a dana 44? I used to use them years ago because they were a tad thicker

That's exactly what I was told

Thank you all for the insight. I will try it with the thin shims and if it sucks we can swap in the 44 shims.

If the thin ones worked for Gus I should be okay. I'll report bakc with my results.

Need to get on that Dana 60 and some offset shackles. I would like to run a 27" tire with 4 10s once we switch over.

Cool info. I remember wondering where the “thick pack” idea came from cause it wasn’t around 20 years ago when I bought a set of clutches. Sounds like someone got creative with Dana 44 clutches.