91 Octane in a 340?

If you don’t have your tunes blasting you should be able to hear the engine knocking/pinging. It will be most noticeable on a hot day and when going up a hill giving the car some gas. When I was setting my timing, I would take the car for a drive and mat it going up a steep hill to listen for it pinging/knocking. If it did, I’d then back off the timing a bit and try again up the hill.

I use 94 (Chevron) since it’s the only brand/rating that does NOT contain ethanol. The Shell Nitro 93 likely contains ethanol since the pumps do not state ‘contains no ethanol’. The Chevron 94 pumps state ‘contains no ethanol’. I know there are more and more Chevrons popping up in Calgary but not sure if there are many in Edmonton? Yes you pay more the the 94 but I’m ok with that since it’s pure gasoline (and ethanol is proven to attract water/turn to sludge over time and which doesn’t help keep internal passageways clean).