Leaded or Unleaded Gas?
 

I was wondering what you all use in your trucks. The guy I bought my motor from says its out of a '70 car and that I have to use lead additive or the valves will go bad or something. Is that true? Is there something that I can do when I rebuild it so I can use unleaded gas?

Thanks for your advice,
Jared

There is some disagreement on this issue. My take on it is that an undistubed engine has enough residual lead to run quite a while. If you do a valve job you will want to put in hardened valve seats. Several years ago I rebuilt the 300-6 in my 72 and when I asked the guy at the cylider head shop about hard seats he said don't worry about it. 25,000 miles later the seats were pounded out so bad the head had to be replaced.

I looked into that before I went through my rig - the deal is, if you're going to just putter around the farm or around town you can get away with doing nothing.

Once you hit higher revs or highway speeds, though, - you need leaded fuel (good luck) or hardened valve seats for sure.

Somebody did a test of the lead substitutes and found they do work but only if three to four bottles are used per tank of fuel, every tank of fuel. That's easily an extra $20 per fill up. Best to bite the bullet and get the heads worked over, it's way cheaper.

I get mixed opinions also. Some say they fry, some don't seem to have problems. It may well be the way the truck is driven. I'd always used the hardened seats in a rebuild just to be on the safe side. My recently rebuilt engine almost certainly has them. I never actually asked them about it, but I'm fairly sure it does. Pretty much standard procedure for a rebuild these days for an older engine that didn't have them. MK

Thats what I was thinking. I'll have to make sure I specify that I want hardened valve seats when I get the heads cleaned up.

Thanks
Jared

I saw tetraethyle lead addative for sale in Hemmings.