427's mustangs and lead

Assuming it hasn't been rebuilt and doesn't detonate without lead additive: It depends mainly on how you drive the car. If you just cruise it, OR if you restrain yourself to short blasts down the dragstrip you probably don't need a lead additive. But if you run it hard on the highway for extended periods, you'll find yourself eroding the valve seats pretty soon. If that DOES happen, its just a matter of pulling the heads and installing hardened seats and new valves. Not "cheap", but not a total overhaul either. Lead ONLY protects the exhaust valve seats- it doesn't do any good for anything else in the engine.

Assuming it HAS been rebuilt with hardened valve seats: Using an additive won't do any serious harm, but it will cause deposits in the combustion chambers, on the valves, and on the spark plugs (at least it will if its a decent additive.... see below). It'll also start lightening your wallet a bit if you drive the car a lot!

Additives: The ONLY ones worth a hoot are the ones which contain Methyl Manganese Tricarbonyl (MMT). The ones that are a mixture of aromatic hydrocarbons may help reduce detonation, but they DO NOT protect exhaust valves. MMT leaves very colorful purple/red/yellow deposits all over the inside of the combustion chamber and in the exhaust pipes, but is fairly harmless unless you use too much per tank. The aromatic hydrocarbon additives don't leave deposits, but thats also why they don't really protect the valves.

I've only seen one running/driving Cammer in the past 10 years and it was in a Cobra replica. If it will fit there, I would *think* it would fit in a Mustang. But Ford is a distant second language to me, so I can't help you too much. :-)

Thank you for your help with lead additives, I've found it really hard to get straight answers, even from professional mechanics (which worries me to no end) I usually get what ammounts to a shoulder shrug...

I'm not experiencing detonation, and i'm not driving hard. If i ever do need to push my car, i'll be sure to get manganese tricarbonyl based additives.

I'll bet the cobra cammer was mighty fine.

Again, thanks much.

Parts to convert a wedge FE to a cammer are rare and expensive. The '65 FX Cammer Mustangs had the shock towers cut away to make more room under the hood. The wedge 427 would not fit much less with the even wider cammer heads. The front suspension was replaced by half-leaf springs acting like a torsion bar which did not encroach into the underhood space. Only eight were made and they were put together by Holman & Moody. For additional details about this and lots of other good stuff, read "Super Stock - Drag Racing the Family Sedan" by Larry Davis.1967 and later mustangs could take wedge FE motors but the Cammer remained problematic.

If it's not been rebuilt and you aren't racing it but are just driving it like any other street car you should not have anything to worry about and don't need any additives. If you can actually find a true lead additive it would not hurt to use it in one or two tanks of gas. The way the lead in the gas works is that it provides the protective coating during the first several thousand miles of use. After that you really don't need to keep using leaded gas. Of course, back in the "old days" you did keep using it because it was in all the gas you bought to up the octane. But it's not needed once things get coated with lead.

If it has been rebuilt and they used hardened seats, then you have nothing to worry about. If they didn't use hardened seats but it's been running for quite a while since the rebuild you can hope that it got some leaded gas when they rebuilt it. If it's got quite a few miles on it it's probably pretty much proved that it's not in need of lead or you'd have problems now.

As another point of reference, when leaded gas was phased out back in the 70's we had a lot of cars in our fleet that were originally built to use leaded fuel. We switched everything to unleaded and I don't believe we ever had any problems at all with the older vehicles valves as they finished out there service on unleaded.

In England they build cobra kitcars with only 6 cylinders!!!!!!!!!!

Very uncool

Erich

I said "like" putting in a small-block Chevy. Putting in a six is very much like putting in an SBC :-) (grinning, ducking the bowtie emblems being tossed at my head...)