Gas

[Doug Do]

I will be putting gas into my 427/400hp '67 next week for the first time since I got it. What type of additive should I use with the gas :confused Since I am not driving it a lot, do I need a lead additive or just some octane boost?

 

[Mikey1]

Have you ever driven the car ? Does it have some pinging ?

If not you may not need any additive....I don´t use any.

Use premium fuel...eventually mix that with racing fuel that should do in any case.....any lead additves will not help to protect anything....a header of a running engine is glowing red which means guite over 1200 deg centigrade. Lead is evaporated ath these high temperatur....any damping of valves or such a thing isd just a tale that hepls companies sell:L

 

[Doug Do]

There is no pinging what so ever . I guess I will try some 94 octane fuel and a little octane boost at first and see what happens....thanks

 

[JohnZ]

Forget the "octane boosters" - they don't do anything except eat the plating off the inside of the float bowls and deteriorate rubber and cork seals - they're LOADED with alcohol, which then attracts water to the surfaces they've removed the protective plating from. Can you say "Snake Oil"? Just put pump premium in it, and if it pings, add some race gas if reducing the total timing and slowing down the centrifugal advance curve doesn't stop it.

 

[WhalePirot]

Octane is not the only question here

While lead was used as an octane booster, it also protected the valve seats.

If the heads are stock, I'd use a lead additive. The harder you hammer those valves and seats, the faster will they be pounder into the head w/o lead.

The seats can be simply redone during a valve job, to replace the seats with those that will not regress. After '67, the stock valve seats were okay w/o leaded gasoline.
Mike

 

[JohnZ]

Valve seat recession in our classics is, for all practical purposes, an old wives' tale; it's only an issue in engines that are subjected to continuous high-load operation (like commercial trucks or cars that tow trailers at 100mph all day long at freeway speed). The parts-store "lead additives" don't have any lead in them anyway - it's illegal to sell it, as it poisons the noble metal coatings on catalytic converter substrates. You won't find any form of "lead" shown in the ingredients - it's all "petroleum distillates".

 

[IH2LOSE]

I am running sunoco ultra 94 in my 67 caddy and my 66 425/427 vette NO problems I use NO additives I also belive they are snake oil products.Both cars are running retarded timing to avoid knock and pings.
When I purchased my vette the owner of the car prior to me was running cam 11 racing fuel in it eldobrok torker manifold,and a modified holley .And he had the timing set correct and the performance difference was night and day.

As it is now 411's in the rear timing set back and I can GAURENTEED put the car SideWays in all 4 gears. NOT just chirp the gears I mean tear the tires off the rims.Cam 11 always draws a crowd But I would not be able to afford to drive the car