FUEL- OCTANE AND ADDITIVE QUERY

[Guest]

Thanks for all the response. Will get timing checked. As car is not a daily driver will probably persevere with unleaded with the additive.

[Guest]

Yippee! Tried super unleaded in her and she is running great with no pinking!

[Anonymous]

I always thought that american engines ran on low octane fuel any way, I run my `66 coronet(440ci) on superplus unleaded

[Adam]

I run the R/T (std 10.25:1 CR) on Texaco LRP with no detonation problems. Haven't had the heads off to check the valve seats though. When they stop LRP, I have a case of Millers VSP to mix with Super Unleaded.

I understand that lead replacement additives are either potassium based or magnesium? Can't remember which one LRP uses, but I know you shouldn't mix them.

[MattH]

I just stripped a head on a Triumph that had been running unleaded with additive for 4 years, it was a magnesium based one I think (name escapes me for now), and the whole lot is gummed up so the valves wont shut and the seats have burnt. It also seems that the company making the stuff are now hard to get hold of, so maybe the additives from a few years ago that were the classic car solution are now showing up problems.
We have now put the car to a proper unleaded head with exhaust seat inserts