(It would make my day if GT Joey answered this!)

If it was easy to come by, I would run my Series II on high octane leaded fuel. I know VP racing fuels has a lot of options http://www.vpracingfuels.com but I'm not ready to buy barrels of gasoline yet.

I use non-ethanol 90 octane (highest octane non-ethanol near me) and a lead additive.
(Though from what I've read the cylinder heads on the XK engine are pretty hard, and don't necessarily need leaded fuel.)

A couple of times lately when I've turned off the car after a decent run I get "Dieseling" when you turn it off and it kind of chugs for a couple of seconds before really turning off....a sign of too low an octane right?

Can anyone recommend an octane booster to me?? Specifically considering the fact that I'm already using a lead additive? I don't love the idea of 2 different additives going into my gas but would love to hear what you use.

---- And stop the presses. After I wrote the above, I found this article which talks about carburetors which don't close all the way or very hot engines. Darn it if I don't live in Florida and wouldn't be surprised if a carburetor is sticking. Still - would appreciate your thoughts, but realize that Octane isn't the only possible answer. Here's what I found: https://en.wikipedia.org/wiki/Dieseling Thanks!!

Thanks!!!!!

Submitted by cf160@yahoo.com on Wed, 09/09/2015 - 09:08

Joey is right. You don't need lead or Octane booster. Mine is a series 2 with 42K miles on it. It only diesels when it gets carboned up from too much driving in the under 2000 rpm area. I can use any fuel and it performs great. I use 91 octane to escape the dreaded "Ethanol" , but it will run fine on anything,
Keep everything clean and DRIVE it a little hard once a day.But don't hit anything...
Dave , In Ottawa, Canada at 90 degrees F.