[patrickt]

I don't think it's going to be your timing or the size of your cables. If you're lucky, it's a bad connection and the voltage drop will tell us that. An easy way to eliminate the "too much timing" factor is to just pull your coil wire when the car is hot and will not crank normally. If the car then cranks beautifully (but obviously won't start) then timing is indeed a factor. If it continues to crank slow and hard, then the timing had nothing to do with it. One nice offshoot of the voltage drop test is that it forces you to actually put your fingers on, and to take a hard look, at each connection from the battery, to the solenoid, to the starter, and the ground circuit as well. It could be something as simple as a loose battery terminal clamp. Read that article carefully though. It's important to start your test from the actual battery terminal itself (not just the clamp that goes around the terminal).