Guys - I am not a mechanic but I am observant.
I had a 66 with a 396 back in the days of leaded gasoline. Before I buy a memory - what do you peopel do to the engine or gas in those old high performance engines with the nolead gas we have today? I thought the lead was to lubricate the valves. Is there a conversion you all do? Is there an additive you buy by the case? Inquiring minds need to know.
I BELIEVE THERE IS ADDITIVES YOU CAN BUY, OR HAVE HARDENED VALVE SEATS INSTALLED IN YOUR HEADS. A LOT OF PEOPLE DON'T SEE MUCH ISSUE WITH IT AND DON'T WORRY ABOUT IT. I THINK IT IS MORE A CONCERN WITH CARS THAT ARE DRIVEN FREQUENTLY OR DROVE HARD.
Lloyd, I usually put a bottle of lead additive in the 64 Catalina's fuel, about every 3rd. tank. Can get it at CTC, NAPA, Car Quest etc. Some owners here say you don't need it, but have seen valve seat failure where the "seat" recedes into the head!!! Long hauls at Hwy. speed seem to be where the damage occurs Or severe useage { I encounter both} & I also use "Octane" booster if I can't find 94 Octane for the 10:5 to 1 compression in the 389 Runs poorly on anything less w/out the "booster"
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Some times I wake up GRUMPY, but today I let her sleep in !!!!!!!!BLACKSTOCK Ont.
I use a "lead additive " ( which by the way says its for off road use ). Used to be able to get it in Canada but lately I've only found it in the US. $5 for enough to mix with 160 US gallons. Its in one of those bottles where you just squeeze and measure out the amount you need. Not sure if its that effective but its cheap insurance. But then I'm not one for high revs, fast starts or prolonged high speeds.
Lead additive and harden valve seats were once thought to be a requirement when running unleaded gas in engines intended to burn leaded gas, but it's been found they're not required.
The above advice came from John Sawruck / Pontiac Engineering.
If you need or want some I have 104 + octane and lead additive, about 50 gallons left. It's nasty stuff so pick up in Toronto is advised. I gallon cans imported from the USA. $15 per gallon. That should last you a couple of years. Let me know by PM.
We've put about 37K miles on our 4.10 geared L78 Chevelle since buying it in 1998. We've had no fuel related problems beyond having to retard the timing as the octane levels drop. Many times, the burned out seats are the result of a poor valve job and seating of the valves. Timing retarded too much puts a lot of extra heat past the exhaust valve and that doesn't help things either. A few years ago we had a '67 L30 327 Chevelle. It also had quite a few miles with unleaded gas with no side effects. It had over 90K miles on it when we sold the car and it was working fine too. With putting hardened seats in big block Chevy heads, especially for the larger valve sizes, there is a real possiblity of hitting water.
-- Edited by Keith Tedford on Friday 23rd of December 2011 05:30:37 PM
