Paul,
Fox Mfg does not sell Lew Woolard's Silver Foxx mod'ed engines. As Marvin D and Joseph mentioned, there was an article in Stunt News, #33, Jul/Aug 1989 - not by Lew but about Lew's mods.
I have a copy of the article somewhere around here, but can't promise how long it will take to find it again.
The Silver Foxx mod has had a great reputation for at least the 24 years since the article appeard. The engines might be even better with the factory ABC sleeve & piston reworked to Lew's timing and porting.