Delco Motor Generator

Unknown

Need diagnosis from you guys. . . When I mash on the starter pedal with ignition switch off the starter is strong and turns quick. However, when the ignition switch is pulled on the starter generator acts like a low battery or bad connection, but if I push in the ignition switch it just takes off again. There are only three choices as I see it? 1) inside the starter generator short, 2) ignition switch or wiring around it, 3) coil energizing and shorted. I pretty much have ruled out 2 & 3 since the coil is new and in good shape and the car runs ideally once started, the ignition wiring is low voltage 12/14 gauge, and the amp meter reads appropriately the whole time (no spike) The car is wired 100% original including the delco short safety coil in the ignition switch. 00 gauge battery cables with factory lengths and connections. During a quite brief 140 mile day this problem emerged around 50 - 60 miles making the afternoon parking choices require a hill or group of passers by to start it. I do not crank because I'm quite civilized when it come to my model Js.