engine runs on

[bmcecosse]

Don't allow it to knock or even pink !! If your compression ratio is standard then knocking/pinking means the ignition timing is too far advanced ! My CR is ~ 10.5/1 - on a modified 12G295 leaded head - I just use standard unleaded with no additives. Goes very well indeed - been like that for 5 years (but only summer use - driven hard though !) and it doesn't pink. And the exhaust valve gaps have never moved. Still has 170 psi compression on all bores - which is a shame because I am looking for an excuse to fit an even bigger valve head !