HI, have just joined up recently mainly due to the wealth of info and advice offered here. While I don't own a Mustang I do have a Cleveland in an XWGT and this site comes up a lot when searching for tuning issues etc with the 351 so hope its OK to ask a couple of questions
Bit of background on the engine which is original to the car and rebuilt by the previous owner approx 3000 miles ago.
Pretty much 1970 factory 4V rebuilt with a PH 2 grind cam ( all I know on the cam)
20 Thou over, std intake manifold with factory 780 Vac Sec Holley, single point Autolite Dist. and std exhaust manifolds.
Intake manifold Vacuum is 9" at idle and fairly steady
I have a concern over the total timing reading (not pinging that I can hear) so was hoping for some advice.
Initial timing I set @ 8 Degrees at 750 rpm idle with ported vacuum advance still connected but when you increase that to 3000 the timing maxes out at 40/42 degrees, with the Ported Vac plugged timing maxes out at 20 degrees total.
I took some readings through the rev range too.
Ported Vac advance connected
750 Rpm - 8 Deg
1500 - 13 Deg
2000. - 23 Deg
2500 - 30 Deg
3000 - 40 deg
Vacuum advance plugged off
750 rpm 8 Deg
1500 - 10 Deg
2000 - 12 Deg
2500 - 17 Deg
3000 - 20 Deg
Have set the dwell @ 29 but that drops to 23 when you give it a quick rev to say 2000 RPM but doesn't seem as bad when you slowly increase revs to say 1500 so thinking the Dizzy may be a bit worn or is this normal. Also with the points gap set to specs of 19 thou ( from memory) the dwell is in the low 20's so had to close the gap to 15 thou to get the dwell anywhere near 29 degrees.
I guess the timing advance will change when on the road under load but just a bit concerned it might be doing damage over time if it's pinging and I can't hear it so any advice would be greatly appreciated.
Cheers Phil.