When I was a kid I used to swipe old car mags from my grandparents basement. I even still have some. I always loved the ads and the cool products that are now no longer available. One that I remember seeing in some '68/'69 Hot Rod magazines was for Varicam. It's basically a centrifugal advance for your timing chain. There is little info available on the internet but last night I ran across one on ebay. Check it out: http://www.ebay.com/itm/Chevy-Small-Blo ... ts&vxp=mtr I'm sure there must have been reliability issues or they'd still be around. Still, I always thought it was a cool concept. The OEs didn't really start doing it until the mid '90s and GM is really starting to use it alot now. Funny to see a "gimicky" product from the '60s being employed and marketed as high tech today. Any of you guys remember these or have any personal experience?