72' camaro 350. Haven't ran it for over a year. It will not turn over. Put in a new starter, selenoid, battery and cables. Ran ground to block, frame and body. I have all wires disconnected from starter and using a switch to s terminal to bypass everything. I have 12.7 volts at starter during attempted cranking. It will only turn over about a 1/4 turn. I can turn it over by hand though. I pulled the plugs not knowing what else to do and it turns over.