They both use a shroud which attaches the fan. We were required to modify the PEP66 with a Dremmel in order to fit it on the VP6. The PEP66 is designed for Slot processors, not Socket, and will require modification if they are to fit on a Socket setup. The PEP66 is quite a bit larger than the PAL6035, too. Although CPU shims have helped us greatly, careless users have been known to short out AMD processors with electrically conductive shims.
Many people are just plain careless but accidents do happen.
I no longer recommend any shim that is electrically conductive, they are just too dangerous to use. Now there is a new shim on the market that is also non conductive. This one is from CPUfx and is called the DTS440. You can read more here . I've been at work updating my voltage mod article.