Model B Distributor in a Model A

[Jack Shaft]

Or you can use a pointer and mark TDC, then you can use a timing light.You can buy a degree scale or just use your eye,5 degrees advances is 1/4" at 500 rpm...the engine likes 1 degree of advance per 100 rpm max at 24 degrees.by rigging a tach dwell meter and using a timing light you can 'map' the advance...5 degrees at 500,10 degrees at 1000,ect..