which type of gasoline?

[petert]

My restored '73 3.0 CS is ready to hit the road. It has original 87k miles and I will use it as a frequent driver. Which brand and grade of gasoline is best to use and what should I expect down the road regarding the use of our current gasoline? thanks, PeterT

[ScottAndrews]

I run only Chevron Techron super in my 635. This is the gas of choice for most of the 635 (M30/M90) crowd. For higher compression engines (like my M90 Euro motor) I add 25% toluene to the gas to get ot from 91 octane to about 97 octane, but that probably isn't necessary or pratical unless you are running a high compression ratio.

S

[Honolulu]

so I get 87, where-ever it's least expensive. Running stock motor, ignition, points, and timing, unopened in the 15-plus years I've had it.

[x_atlas0]

Considering the car is designed for 87 and the car has no advanced timing controls, running premium is something of a waste. I run midgrade, so 89.

[decoupe]

25% Toluene? Wow - you need full hazmat suits just to pump gas! That has to be more than 97.

I run my moderately modified 3.5 dual carb on anyone's 91 with no problems - haven't tried mid grade. There are a couple of stations in the city that sell 96 (gas/ethonal blend) just down the road from Race City Speedway. Definiately a difference in performance driving - in bumper to bumper not so much.