just spent a couple of hours trying to establish true TDC and I've come to the conclusion that its at 4 degrees ATC.
It'll be interesting to get a strobe back on it and see what that shows 4 degrees plus another 4 is 8 degrees - too much advance???
If your true TDC is really 4 ATDC (mine was 5 ATDC) then 4BTDC would be your 8 degrees. Do check up to 4000rpm to see if it gradually rises to around 28 degrees (the distributor will be fully advanced). Of course once you have it set take for test run on an incline with the engine under load (high gear) to see if there is any pinking, if there is then back off a degree or two and test again.
Over here the quality of petrol varies greatly from pump to pump and I have found when touring that too can have an effect on the performance, I try to use Shell V Power as it seems to be consistent and works best.
