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I was curious what all of the "senior" Cat owners recommend to use as a fuel additive?

Since I can't get leaded, 100+ octane fuel at my local Texaco...

What are some suggested additives for a 1970 w/a 351C, 100K miles plus, running in 105-115 degree Phoenix, AZ (yes, it really is that hot for 3 months... ugh!)

Thanks,
Chris
 

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Are you having a particular problem that makes you think you need an additive? If you have a stock engine (with 100k)you shouldnt need 100+ octain fuel. Are you worried about the lead free fuel? If you do just use any lead substitute. People will tell you different things about lead free gas and the detrimental effect on the exhaust seats. My way of thinking is I have seen some of the older engines that have been run with a steady diet of no lead and most have not looked pretty and if your doing a valve job its silly not to go with hardend exhaust seats. If you have a pinging problem I have used 104 octain boost some what and it will help to a degree. Hot air will richen your fuel to air mixture so if any thing you shouldnt have a lean condition that promotes detonation but its something you should check.mm
 

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Chris, I live on the Oregon coast where, it hardly ever gets over 70 here but I don't think it would make a difference. I use octain booster in my 69 Eliminator and my 525 HP 440 motor. The best I've found and, that are still priced resonably are, NOS 108 its one of the few you'll find that actually states, that it raises the octain level 03 points. If you cannot find that brand, I have also used Outlaw 108 in the Blue can red bottle is not a good. hope this helps.
 

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Octane boosters

Most octane boosters are a waste of money.

Back when our area went totally lead-free, many of us with performance engines were worried about running 93-94 octane unleaded. We started using 104+ brand and had terrible results! The cars still pinged and the worst part was the brown deposits left on the plugs. You really couldn't tell what was really happening with the combustion, so we just quit using the stuff. Other than lightening our wallets by $8 a can per tankful, there was no benefit at all! There was no noticeable difference in running with- to running without the octane booster. We scrimped by by retarding the timing a little bit and that cured just about everything.

Now lately, there seems to be a resurgence of racing interest and a lot of the gas stations in the area have racing fuel, at least in the summer months. Yeah, yeah, I know it says 'Not for Street Use' on the pump. We are not allowed to pump it dirrectly into the cars, so we must pump it into five-gallon containers. Off premisis they couldn't care less what you do with the stuff. For most street cars, even hot ones, you really don't need the stuff. But if you are thrashing your car at the track, a couple of gallons per tankful seems to be more than enough.

BTW, my wife's 70 Mach 1, with its 351C-4V high compression 10.75:1 engine needs only about a gallon of racing fuel to 20 gallons of gas if we're gonna thrash on it. Most of the time, we just run a high quality 94 octane unleaded with no adverse effects.
 
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