Engine Additives? Are the Claims real?

[kombreeze]

I'm thinking about using a lead additive in my truck. 68 chevy with 327 heads so I thought it shouldn't hurt. Actually I found a case of it at Big lots for like 50 cents a bottle. Each bottle is good up to 30 gallons. I can buy enough to last me until the end of summer I plan on driving it. Another question is I may have is how do you guys like the Oil additives. Since I have a mystery motor I figured it shouldn't hurt....

So what additives do you guys use. Or better yet whats your experience with them. There are always so many claims for engine oil and fuel.