gas?
 

First of all, thank all of you for your great advice!!!

I'm a new Chevelle owner(1970) and I'm about due for my first tank of fresh gas. Is it better to use lower or higher octane?

I also know that I need a lead substutute additive.

-GM:confused:

This is your 3rd post asking about your 1970 Chevelle but you still haven't told us anything about your car. To give you good advice you need to tell us a little about it, like what engine is in it. Is it still 1970 stock or has it been rebuilt, modified, replaced? Some of the questions you ask just don't have a 'one size fits all' answer.

In general you would probably need to run a higher octane gas but again, that may not be true for your particular engine. Lead additive, don't really believe it's needed. Some will say if it's a stock 70 engine you need it but there are a lot of stock engines running fine without it.

A higher octane gas will let you run more timing advance. That can help with performance, fuel mileage and it will run cooler. Do you need a higher octane? Can't answer that, don't know anything about the engine or how the timing is set now. To be safe I would say use premium so you don't risk pinging, detonation which can ruin an engine.

The highest octane you can find (I use Shell). I also use Red Line Lead substitute (the good stuff is not made anymore) and a fuel treatment for ethanol. I think the increase in ethanol is more of a problem than the lack of lead.

Thank you for all of your help!! I have a 1970 Chevelle 307 automatic.

If the engine is relatively stock, then it's compression ratio is approximately 8.5-9.0:1 which should run fine with the lower octane fuel at stock timing.

Mike

Hi green.Waving