HELP! truck won't crank

[69ride]

I just put the cab on and wired up the ignition, new soleniod on starter. Battery has 12.50V. 12.50 volts at starter, 12.50 volts at alternator. Jump in the cab, turn the key, nothing. multimeter shows 12.50 volts at starter. now the history..

When I took the starter off it had a wire going to the R terminal and a wire going to the s terminal. The truck has HEI installed on it so I don't need the wire going to the r terminal right?

Second question the wire that i clipped off going to the r terminal was white not yellow and it was tied in with the wire that goes to the distributor(pink) at the firewall connector, should this wire go back on the r terminal?

The ignition switch i have was given to me so i don't know if it works or not. I am going to go back out and see if i have power going to the switch. and hopefully when i come back in there will be a mess of info on here

Hope this is as clear as mud.

the engine is a mid 80's 305 and the cab and ignition switch are from a 67 GMC c10

Thanks in advance guys and girls