Yes there is. Here are 2 more pics. Looking at the cover you can see the deformation that happens from the roller as they slam the cover and add additional #850 of force. The other picture is of rollers and the shim that sits in the PP roller channel on the hemi clutches. The rollers are pressed together. They can get corroded and stuck. I used a 16mm socket that allows the outer wheel to fit in, but catches the inner roller which is larger. I can press them apart in a vice to clean. Looking at the plates from previous pictures, I have seen the roller channel on the plate deform also and groove. Probably from a stuck roller. So I believe the hemi had these added pieces for strength, but also free movement of the rollers for shifting on the drag strip. Reason hemi only had 3 vice 6. The other issue is the pressure plate was also made of a better material and to make it more explosion proof. Similar to a forged versus cast crank. The plates can be rung, just like a crank.
I have taken apart about a dozen clutch's in the last two weeks. OEM B&B, reman B&B, Hays, Weber, and a Shieffer. The ability to compare side my side, the various parts is insightful, and I document. Also helped explain why a Hays had borg and beck parts. I think in the early day they were not a true manufacturer, rather they bought parts form Borg Warner and assembled them, or were doing the remanufacturing business. Some covers are clear B&B with patent info, and made in chicago. Other covers have less info, and then much newer clutches have none of the original B&B data on them. So I think as Borg Warner moved on, Hays, Weber, Schiefer and other moved into manufacturing to where we are now with Hays, Mcleod, Ram.
The other thing to clear up is the 11" large pattern pressure plate is the exact same as used in the 11" scalloped. I have seen the same Casting part number in both types. They are full 11" dia with the rectangular notch at bolt holes. What is different is the true 11" scalloped used a 10.95" clutch disc. That extra .50" clearance along with the special bolts is what kept the disc from catching the cover. The 10.5" and 11" pressure plate have the same lug and spring boss locations. So that you could actually install a 10.5" pressure plate into the 11" or 11" scalloped housing and have everything line up and work.
I have already had two of the best pressure plates resurfaced. So the plan is to rebuild the best housing to the original specs for use on my motor. Ideally I would like to find an 11" and 11" scalloped hemi housing. I do believe I have 2 of the 11" scalloped housings but wanted to confirm the model number as 383 or 440. The model # I have is 1828.
