Originally Posted by ap72
Oh, its very simple, if you have 34* of timing at idle, and you're idle is set below 2,700 RPM or so, which I expect for that cam is probably around 900 RPM. Then it would be detonating a LOT from take off- that's kind of the whole idea behind having mechanical advance on a dizzy- so you have more timing when you need it, but not too much when you are carrying a high load at low engine speeds.
to simplify it 34* timing + that cam + that compression (at take-off)= BOOM!
Too many factors to say that is an absolute. I ran 9.5:1 with a 218/224 cam with 110 LSA and was able to lock out my mechanical and run 36* all the time PLUS ported vac.
Chamber design, altitude, thermostat temp, intake air temp, quench, piston design, carb tune, exhaust design/scavenging, stall speed, auto or manual, if the cam is installed straight up or advanced/retarded... the list goes on.
To say that its definite that he'll cause damage is pretty premature at this point.
Initial timing is a pointless number provided it doesn't cause problems elsewhere in the RPMS/load. You can get away with a lot more low RPM timing with an automatic since heavy loading (lots of right foot) will always mean elevated RPMs.