I just came to own a 1966 Coupe. It is 100% original with 45k miles. Was my uncles car. He is the original owner and the car had been in the garage for almost 60 years. It is in showroom condition. He Did some engine work. car is spotless. Came with a few trophy's from shows he took it to. I think the gas in it must be very old and the heater core has a leak. Car has not been driven on many years. I believe the gas is very old so I has to change that out. Any suggestions on type of gas?? Any other comments or suggestions welcome. Thanks in advance

 

Unfortunately cars built before 1970 ran on leaded gas and I'm not sure if you can find that anymore. At some point you will have to do a valve job and change the seats to accommodate unleaded gas. You didn't say whether 6 or V8 but split the difference and try 89 octane. If you hear knocking, switch to a higher octane.

 

Thank you - Its a 289 k code which has been bored. I am thinking of trying the Sunoco 100 octane Fuel.

 

I don't think you need to get that serious unless the engine has really been modified with a big cam and high compression. Stick with 91-93 and you will be fine. If you know it's been bored which is normal for a little rebuild, do you know if the heads have been updated?

 

Yes - It they were. Has a pretty big Cam in it. Modified exhaust manifold. going to try to post a video

 

 

Sweet looking car. I still wouldn't run 100 Octane however. Higher octane isn't necessarily the answer and will actually hamper performance and economy if the engine isn't really built for it. That's a race fuel meant for really high compression and performance at high RPM. Your car looks more like a really cool street machine with streetable high performance in mind.

 

Changed out the old gas and put in 93. Started up ran OK. Doing a complete fluid change/ tune up and carb adj. Will see how it runs after that. Thanks again.

 

Good to hear that. Best of luck with it. Sweet ride.

 

They sell lead additive you squirt into the tank each time you fill er up.