I am about to take delivery of two C2 Corvettes. One is a '63 L67, 327/340 hp. The other is a '67 with a L68, 427/400 hp. Both are matching numbers and have been frame-off restored to a very high standard. One is a NCRS Top Flight winner.

My question is... do I need to use lead additive or octane booster in either car or both. I do not have access to any fuel other than premium pump gas.

Thanks... Dave

 

Nope.

 

Additives won't help.

 

I've read elsewhere that the lead in the fuel acted as a lubricant, and therefore should be added to unleaded fuel for these cars. Have also read octane boost Is not necessary.

 

You read that concerning unhardened valve seats causing "recession" into the head due to overheating from lack of the lead. Unless you are full out drag racing all the time the additive is a total waste of money...

Its just a false sense of comfort for the paranoid. You can send me the money you would spend on the additive and I'll text your cell phone once a week and tell you "Everything is OK"...

 

Hey I could use that kind of comfort! Hadn't read those specifics before, but good to know. Thanks for the explanation.

 

while it is true that lead does add some slight measure of lubricity to valve trains, it's main purpose waay back when, was to help control pinging or knock. it is terribly filthy stuff and does more harm than good to an engine over time.
off the shelf octane boosters are pure snake oil.....

 

Dave, you haven't filled out your public profile yet, so don't know where you are located, some states have 93 octane available and some only have 91 octane. Also, elevation is part of the equation too. If you have 93 available and you are at sea level, no problem. If you are at 5000 feet and only have 91 available, you might have some ping problems.

 

I'm not sure where you are located or what kind of premium gas is available to you, since your profile is silent on details.............. If you've got 93 octane premium without ethanol available, I would agree with the above responses.

If, on the other hand, you get the same 91 octane cr@p we have here in Kalifornia, and/or you want to be able to advance the timing to enjoy the full performance potential of your engine, you might want to try this option.

Go to your local hardware store and buy a one gallon can of Toluene - it's in the paint section as a solvent. It will cost about $16.00. Being VERY careful, using a funnel and rubber gloves, add it to your gas tank when it is 3/4 or more full. Pour it s-l-o-w-l-y and carefully. Do NOT get it on your paint or skin. This will both boost your octane rating (maybe 3 - 5 points) and keep your system clean. Toluene is one of the major fractions of gasoline that refineries use to boost octane. It is also a major component of Techron.
The 12 or 16 oz additives you can buy just don't have enough volume to make any significant difference. One gallon does! I know from personal experience - I use it in my '67 Corvette
(and Mustang ) frequently.

I'm pretty sure some of my favorite Forum members will chime in and tell you this is a bad idea or a waste of money, but I can tell you it lets me advance the timing to 12* static and enjoy the power with no detonation. The good news is I won't have to hear those other members criticism, since they're on my "ignore" list!

 

Well, looks like I'm wrong again. Claysmoker has patiently explained to me why he thinks my brain is full of wild blueberry muffins. I wasn't wrong, I just had it backwards...must be this darn dyslexia...it's the lower the altitude, the higher the octane required to prevent detonation. Anyway, ask Dave, he knows a whole lot more about this than I do.

 

My humble thanks to all who have replied to my question. I live at 1,700 feet above sea level... on a mountain... most of my driving will be from sea level to around 3,000 ft. When I was a kid, I used to like to drag race but now, a geezer at 64, I just want to experience the thrill of driving my Corvettes for the joy of it. I will see how it goes the first couple of tanks. Passport Transport is scheduled to deliver my '67 tomorrow A.M. Thanks, Dave

 

They will run and some here even think they will run just fine. But they will never run as good as they did in 1967 with "Chevron Custom Supreme."

If you just stop by Pearson Air Park / Grove Field with a 5 gallon gas can you can pick up some Avgas 100LL. That 5 gallons of leaded gas mixed with the rest of a full tank of the best highest octane pump gas will make your 400/427 happy. Otherwise it will ping, unless the timing is dumbed way down. Others will say I'm FOS, but I've lived/BTDT with these cars since I bought my first C2 new in 1967...........from a pilot. Phil Fields of Fields Chevytown in Portland.

 

Phil... I was told at Pearson that I needed a pilots license to purchase 100LL fuel. DG

 

Phil... if you care to give me your phone number, I would like to talk to you. Thanks, Dave

 

I have always used lead additive on my Corvette. Use it on 95 octane gas.
RON 95 according to Esso Norway
Lead per gram is 0,001

I just looked it up on the internet and the 95 and 98 octane we use is the same as the US 87 and 91

 

[QUOTE=ztheusa;1578517467]...But they will never run as good as they did in 1967 with "Chevron Custom Supreme."

What I would give for some good old Sunoco 260...that dial on the side of the pump was so cool...