1969 and gas question
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
It would help to know the history of the car and which engine you have. From what you said it sounds like the engine has never been modified. If that's the case it won't have hardened valve guides & seats on the heads. To save those from premature wear, as long as you don't have any pinging issues, all you really need is a lead substitute which has a lubricant to protect those areas like lead would have. You can get a number of different brands at any parts store that will do the trick. They aren't expensive & all you do is add a few ounces each time you get gas. They won't increase your octane, just protect the heads. Hopefully this helps. 
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
When I bought my 70 it had a bottle of additive that I used at every fill up. Like he said above it is just a couple ounces and just takes a second. If I remember correctly it can be had at Wally World also.
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
I use Maxlead 2000. Check out their site. www.maxlead2000.com Blend for about 100 octane and yopu will get much better milage plus more power and cooler temps.
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
Originally Posted by jacobsed
It has the 350/350. 11:1 compression.
Now, these are supposed original miles. What if the engine was rebuilt?
Wouth heads now have hardened valve seats?
Now, these are supposed original miles. What if the engine was rebuilt?
Wouth heads now have hardened valve seats?
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Max lead has real tetraethyllead. It works.. Other bosters don't do very much if anything. With max lead I cannot make my engine ping, even in hot weather, A/C on and under load at low speed in 4th gear.
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
Originally Posted by Larry B.
Max lead has real tetraethyllead. It works.. Other bosters don't do very much if anything. With max lead I cannot make my engine ping, even in hot weather, A/C on and under load at low speed in 4th gear.
I use Max Lead in my 11:1 CR smallblock & it's great stuff. I'm not sure jacobsed needs it since his engine isn't knocking & he doesn't seem to be sure of the engine's history. If it is truly 11:1 I'm sure he would run better w/ Max Lead, especially w/ an aggressive spark advance curve. If it's not a true 11:1 he may just need the non-booster lead substitute that I referred to before.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,501
From: Little Rock AR
I would not use additives for lead or octane. I have been driving my car around running pump gas and no problems. The compression is about 10.3:1 running flat tops, tight quench and the 350/350 L-46 cam so the configuration is close to yours.
The heads on your car may or may not have hardened seats. No way to tell without tearing them down. No reason to tear down the engine until it needs it. The seats can be checked at that time and replaced as needed.
Hardened seats are over rated for most applications. I did not install them on my 69 Z/28 when I had the engine going together. You will enjoy your car for many years before it ever needs a tear down. If the seats are worn then, the current owner will have to consider seat replacement at that time.
-Mark.
The heads on your car may or may not have hardened seats. No way to tell without tearing them down. No reason to tear down the engine until it needs it. The seats can be checked at that time and replaced as needed.
Hardened seats are over rated for most applications. I did not install them on my 69 Z/28 when I had the engine going together. You will enjoy your car for many years before it ever needs a tear down. If the seats are worn then, the current owner will have to consider seat replacement at that time.
-Mark.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Just use Premium
11-1 engines work ok with only premium. Just dont crank up the total advance over 36 degrees. Your NEVER going to wear out the valve seats with the use of unleaded fuel.
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
hey larry , i bought a gallon of max lead to try in my 383, i havent mixed it as of yeat, but i was gonna try 12oz's in with a fillup(i believe my tank is 12 gallons) thats =1 oz per gallon, so ibelieve i'll be up to 101 octane,im runnin a 488 lift 302 dur crane fiberball cam, heads are 2.02/165-flat top pistons/stroker crank/ compression 10.5to 1-engine runs on 93 octane ,but i wanted to see how it ran with a tankful- for $30. a gallon , and the little bit i really drive this car(heck a gallon should last 10 fillups) it should last all season-you say you noticed the difference?------carl
Last edited by carl a; Sep 29, 2004 at 05:51 AM.
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
12-14 oz per 20 gals is what I use. I drive daily so I actually have a container marked at 9oz so I can put in 15 gals at a fill up and keep a constant ratio. BTW... Big blocks of the same compression ratio as smal blocks are a lot more sensitive to octane rating.... Especially in hot weather. I noticed a big reduction in engine temp as soon as I added max lead. like.... 20 degrees!!
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
i cant wait to see if she will run any better- hell she comes outta the hole like a scalded dog now!---also i wonder if the lead will hurt at the time of emission testing!!!!----
Last edited by carl a; Sep 29, 2004 at 05:11 AM.
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
You will probably be able to advance the timing at least a few degrees. I was running 6 initial and 28 total with no vacuum advance. Now I run 6 initial and 38 total but I haven't hooke the vacuum advance back up. I'm happy with it like it is. I checked milage before and after.... 10.3 before and 15.1 after adding the max lead. I cheched it on the same route to and from work over a week so I feel the result is accurate. That is mostly on an expressway at 70mph with 3.55 rear.
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
i get 17 mpg on the highway since i changed the tranny over to the 700r-4- from the 3 speed turbo- and im runnin a 373 rear-the overdrive was the best mod i have done- heck i think my milage was 7 or 8 with the old trans---i got a 79 harley with 16,000 org miles on it& was gonna try the max lead in her also
Thread Starter
Racer
Joined: Jan 2004
Posts: 463
Likes: 0
From: South Haven MI
Alright you Nancy's.....thanks for the replies. I might (but I doubt) be able to track down the history to know for sure on the engine config. But if I can't, I can just use some non octane boosting lead additive to be on the safe side and not worry about anything correct?
