I have a 1970 350/350 that is an orginal motor-it has never been out of the car. What lead replacement/additive does everyone use since all the gas is now unleaded? I have looked at aviation gas (100 octane low lead) but the airports won't sell it if it to be used on the road. (similar to the regulations for off road diesel). I have also found racing gas at a local fuel distributor (110 leaded octane) but it is $4.50/gal!!!. (maybe more now!!)

What is a good lead substitute that will work and won't cost an arm and leg?
Thanks
Mickey

I don't know how good it is, but I bought mine in the auto dept. at Wallmart...don't recall the name of it. I think the mixing ratio is one once to ten gallons of gas, and the cost for a 48 oz. bottle was less than $10.00...I do know that the previous owner did not use the stuff; however I do, because I read you're supposed to and I have not noticed a difference.

Forgive the ignorance, but I'm wondering what the reason is that you need to add lead? I thought the important factor was the octane level? What's lost by not having lead in the mixture?

Older engines did not have hardened valve seats. The lead was to cushion the valves to avoid premature wear.



Dave

SundayMoney said: Older engines did not have hardened valve seats. The lead was to cushion the valves to avoid premature wear.

Ahh - thanks for the quick answer! So, by "older" do you mean just about any C3? Does everyone - or should everyone with a C3 add lead?

I don't know the exact cutoff date. Perhaps someone else will chime in. I seem to remember it was about the time emmission control started to kick in. Maybe '72 or '73?

Dave

The date the emissions took a turn was in March of 1971. Any one that has a vette before that date should have lead in their vettes. And anyone after April 1971 are O.K. for unleaded gasoline.

IRON 82

From what I've read the best substitute for lead is teflon so try to find an additive listing teflon. Also, according to multiple sources I've read and talked to about wear from not using leaded fuel, they have all said not to worry about it unless you stack up some serious mileage each year. If you don't plan on putting on more than 75,000 miles I wouldn't worry about it. I've been driving a '63 T-bird for 10 years as a summer car and I've yet to see any indication of valve seat issues.