Back in the 60's we used both Schiefer clutch/flywheel assemblies that were aluminum with copper/iron spray applied surfaces and Weber aluminum flywheels that had a steel friction insert. This was for our drag strip only stuff and everyday driver street rods.
Keep in mind that some of us were driving (barely) street legal race cars to our day jobs. Stock clutches did not last and cast iron flywheels and pressure plates were just waiting to come apart, especially with small block Chevies turning over 7000 RPM. We ran the aluminum stuff for safety if nothing else.
Relatively short life was expected on the race cars and they didn't last all that long on the street either. Without the weight of an iron clutch/flywheel, on the street our high end tuned, big cam and over-carbureted, motors would bog as soon as you started to engage the clutch. But, slipping the clutch was not much of an option.
The Schiefer surfaces did not like the slippage needed to get a '56 or '57 Chevy moving on the street and would progressively gall or smear. This made the clutch grab, making you get in and out of the clutch to get underway.
Weber flywheels, their pressure plates were steel, had their own problems because of the splippage as the inserts would warp, reducing clutch adjustment to where you might not be able to fully disengage the clutch.
We all got real good at changing a clutch and flywheel in less than 30 minutes after dinner so we could drive to work the next day. Needless to say, our parts supplier loved us.
First post so must apologize for not figuring out how to provide a link to Paul Schiefer on the SEMA (Specialty Equipment Market Association) web site.
