There is enough lead built up on the face of the valves from years of running leaded gas, that it probably will never hurt your engine, the lead acts as a cushion between the valve and the head. However, if you grind the valves, you should then install hardened valve seats. If you do not the valves will surely eat into the head. I have taken enough engines apart and have seen the valves recessed into the head 1/8".

I use regular unleaded but I doctor most tank fulls with lead substitute gas additives. Since I'm ony driving a few hundred miles a year I don't know if that is enough or not.

There isn't a lead substitute on the market that is even worth a plugged nickel. I went to a seminar on fuel additives put on by Shell Petroleum. As it states--lead substitute--- there is no lead in it, first it would be against the law if there was. Lead was added to fuel in the 30's to keep the valves from recessing into the cylinder head and losing their adjustment. Once a valve starts to tap, it has lost its adjustment and is now slamming too hard against the valve seat. At this point it is doing damage! So keep your valves adjusted. Engines that have been running leaded gas all their life have enough lead built up on the valve face that the couple hundred miles a year we drive these cars will never hurt them, unless you let your valves get out of adjustment, and then it will start to hammer the lead off the valve face. Engines that have been overhauled and have had the valves and seats ground should be OK for driving 500 or so miles per year. It will take approx 10,000 miles for the valves to recess into the head far enough that the valves will leak bad enough to misfire. If you plan to race your Crosley, or run high revs like I am going to with #19, then I suggest installing hardened (stellite) valve seats, and sodium filled valves, then you have nothing to worry about. I hope I have helped you and not confused anybody.

There is a real lead additive, it is about 10% of what used to be in the real leaded gas in the 60's, but it is enough to keep the lead built up on the valves. The only trouble is that it is made for small aircraft engines, and is very expensive. It is available at small airports that have repair facilities. IT IS ILLEGAL TO USE THIS IN ANY AUTOMOBILE ENGINE!!! I am only telling you this so you don't hear about this from someone else and go buy some to put in your car, thinking it is OK, It is not!! Most repair facilities make you fill out a form when you buy this stuff, and they do forward them to the D.O.T. Besides 10% lead is not worth the selling price of the additive versus the cost of installing new valves over a given time period.

I have come across two fuel additives which supposedly are lead substitutes. The first is AlemiteCD-2 made by Stewart Warner that is added at the rate of 0.5 oz per five gallons of fuel. The second is Index DSP, made by Index Industries of Caledonia, Michigan. It is diluted one oz. to 9.3 gallons of fuel. Both are supposedly replacements of the lead that used to be in gasoline for internal combustion engines. Is anyone familiar with either of these and if so do they work?

I have used the cd-2 for years and have had no problems. I have a 42 ford gpa that has used it for 15 years and no problems.