Muscle car owners. what gas do you use?

[FrustratedUser]

Just in case I someday might buy one.

How do the old engines cope with unleaded fuel. Any additives needed?

 

[CraigRT]

I was under the impression unleaded was fine (87 octane regular)
but the only problem is when running leaded fuel in an unleaded recommended engine.

obviously that's not too hard to avoid, this day and age.

 

[Antisocial Virge]

I remember reading about the probs with unleaded gas and the old valve seats. I remember some gas company said they had additives that fixed that. In the end I just ran whatever came out of the pump and never thought again about it. Never had a prob and never heard of anyone else having any either.

 

[dave127]

I know that my dad uses sunoco 94 octane only...he has never had a problem either...straight from the pump

 

[FrustratedUser]

OK.

How about the high compression engines out there. Is premium good enough or is a mix of race/pump gas the best?

 

[PG]

Most engines from 1970 and before need high octane because of high compression and they did have soft valve seats. It would be good to use a lead replacement for every tank. You can get some at any automotive store. Just do your research first and you'll be OK.

edit: you can get ocatane boost at the same time you get the lead replacement. Some products might have both in one bottle.

 

[amdskip]

Originally posted by: Antisocial-Virge
I remember reading about the probs with unleaded gas and the old valve seats. I remember some gas company said they had additives that fixed that. In the end I just ran whatever came out of the pump and never thought again about it. Never had a prob and never heard of anyone else having any either.

Thats exactly correct. Depends on your heads/valves.

Just run straight high octane racing gas, don't mix it. We used to use racing gas but switched over to alcohol as alcohol has much better cooling properties allowing the entire motor to run cooler.

 

[FrustratedUser]

The car I had in mind is a 66-67 Mustang. Not very high compression but still an engine from the old era.
Any problems with regular pump gas there?

 

[PG]

I think you would need some lead substitute and maybe octane boost. If the car has a 289 V8 you'd need to know which version. I think there were 3 versions: 2 barrel carb with 200 hp, 4 barrel carb with 225, and the hi-po motor with 271 hp. Each probably had a different compression ratio.

 

[FrustratedUser]

Thank you!

 

[radioouman]

I used whatever in my '68 Plymouth Barracuda. However, I always ran a lead additive with the unleaded fuel.

I was careful to run decent gas (no alcohol content) in my '75 Plymouth Duster because the carb was so sensitive to different gases. '75 was the first year for unleaded fuel, so I didn't need the additive.

 

[GagHalfrunt]

Originally posted by: FrustratedUser
The car I had in mind is a 66-67 Mustang. Not very high compression but still an engine from the old era.
Any problems with regular pump gas there?

I've got a 1966 289 Mustang GT. It's the 4 barrel motor, but not the "K" code solid-lifter Hi-Po model. It runs fine on regular 93 octane pump gas, every now and then I toss a little lead additive into a tank to keep the valve seats in good shape. Pulling the heads to do a valve job isn't too hard with cars from the pre-smog era, but it's still something to avoid if possible. It *can* run okay on 89 octane too, but is far happier on 93, so since it's just a play car, not an every day driver I don't mind using more expensive gas. A friend has a '68 Mustang with a base 2 barrel 302 and that runs great on 89 octane, no need for premium on that particular car. Of course another friend has a built 454 Chevelle and that only runs well on a mix of regular pump gas and very high octane aviation fuel. It's cheaper for him to buy av-gas and mix it with regular pump gas than it is to buy special racing gas like Cam2. It pretty much depends on the individual engines, but there are still plenty of late 60's classic pony cars running well on regular gas, so you should have no trouble. Just experiment a little with different brands and octanes until you find something the car is happy with. You might need to 91 instead of 89 or 94 instead of 91, but you're likely to find something at the pump without having to resort to racing fuel or av-gas as long as the motor is mostly stock.

 

[SlowSS]

On my Y2K Camaro SS, I use 93 octane with no additives, and it runs just fine.

LS1 engine Compression Ratio is 10.1:1

 

[toph99]

you can buy lead additive from most auto parts stores. you don't need to use race gas or octane boost or anything unless it's pinging from high compression. My friend's 1970 trans am(400 poncho bored/stroked to 460-some odd inches) uses regular 92 octane, he has 9.5:1 compression i believe. he doesn't need lead because he has hardened valve seats. If you had a late 70's car with low compression, 87 octane should be just fine

 

[ROTC1983]

Yeah, I use the premium stuff in my car