Way back when I used to do car maintenance and tweaking I used the following method (mostly Ford engines with carburettors but used on other cars). It was a way of getting maximum advance and therefore maximum performance. It takes account of the weather (need to do it on a hottish day to be safe), other timing settings (vacuum and engine speed adv/retard), points gap and fuel quality.
This method was showed me by a very good car engineer and does really make a difference.
BUT, WARNING as you all know an engine that is pinking (pre-ignition - can provide an explanation if needed!) for more than a tiny amount or for than for any more than a very short time can severely damage itself. I also assume you know and can hear pinking? So, if you are in any way unsure use the book setting. use this method at your own risk....
Get the car filled with your regular supply of petrol, check distributor and points gap, carb condition and check for air leaks etc...
The worst case for pinking is normally when the engine is at low speed, maximum load (1500 - 2000 rpm and top gear) and enriched just after you have pressed to throttle pedal to the floor and the carb has given an extra squirt of fuel (lasts a couple of seconds). So this is something you wouldn't normally do any way.
Drive with the engine hot and do the low speed/top gear pedal to the floor and if the engine pinks retard a degree until it just doesn't pink any more. After setting like this you need to be listening for pinking in case things change but normally it will only be under those extreme conditions. To be honest I used to set the adv so it just gave a couple of pinks under that load but it was my car an my cost if things went wrong...
One thing I did notice that in them days petrol Octane rating did vary a bit so sometimes lower quality petrol caused more pinking other than extreme slow speed load/ accel - a good reason to add a degree or so of extra retard to be safe...
Used that method for years - in fact modern injection engines have "knock sensors" that in effect do the same thing - advance until they detect knocking and back off.
Its years since I've tweaked an engine like that and never on a Morgan so its old school - would value feedback from the more experienced Morgan owners/mechanics and perhaps performance guys as to whether this is a good method to get the max...
I cant say it enough that if you are unsure about this use the book settings. Ive only raised this out of (historic?) interest to see if its still valid (I have a GDI which I cant touch without specialist kit!).
