Originally Posted by GraphiteGray
Super-unleaded is best for your engine, but if your head hasnt been converted to run unleaded with hardened valve seats you'll need to use a lead additive
You dont. Read what Dave says. It's bourne out in practise...Also a fule catalyst such as a broquet is an alternative to lead additive.......trust me it's safe. I've seen it used on vintage cars worth up to half a million pounds, and i'm pretty sure the owners werent taking a gamble