I was wondering about detonation, my 95 econovan definately used to ping going uphill on E10 (that was the 1.8 lt ... mazda F8 motor from memory... dunno what shape the top of the pistons are) but seems you have no probs on 202 Byron? Thats why I was wondering about timing settings. Whether there is any recommended change for 253 and 308. Good to know about that piston shape, and the 202 is pretty tough after all for what it is.

My understanding is that some engines on E10 are typically more likely to knock under load, because the drivers response to slowing down in a traffic condition (say beginning a hill whilst towing) is typically to increase the throttle, if the fuel burns slower than designed for that engine, then the main burn would happen closer to TDC than it would have on (say) super or standard unleaded, untill the increased fuel burn enables the engine to recover and overcome the load. This only holds true if E10 burns slower than super of course, but I think it may do. Detonation is not something you want.

Whilst Byrons experience shows a 202 (flat piston) handles this, it would be good to find out if it is the same for 253 and 308. I reckon, call Shell Australia and ask? Someone there will know, probably they have a list they can provide for 70's and 80's Holden engines. Tell them you're writing for this site and ask if you can display the list here, (and then ask for a free mars bar), you probably wont get the mars bar, but you should get the answer! lol!! They do want to sell petrol after all.