1970 Calais starter ticking when engaged?
 

Hey everyone,
i am new as a member but have stalked this site for a while to solve some of my problems. lol anywho, my question is i have a 1970 calais which is the exact same as the 1970 deVille (472 ci block) and i have yet to get it running since purchasing it with practically a bare block a month ago. The starter was turning so slow that it would occasionally catch on a compression stroke and stop. battery cable is not the problem and the battery is new, with over 500 CCA. so i replaced the starter. Got the new one it, seems to turn faster. say seems because it's getting drowned out by a loud clicking noise. new starter came with some shims, but the reprint original manual i have makes no mention of shimming. Is this a shimming problem or a more obvious starter silinoid problem? like i said, there shouldn't be any reason to have low volts that i know of. i have 12.5 volt in the battery. like to not ruin a new starter, as im about got it ready to roll.

Update on my problem, (still hoping someone will chime in who knows simple electrical operation) i put in new 2 gauge battery cable (positive) and a new starter to frame ground. plus i tested the existing neg post to a random body spot and got no resistance in the ground side of the system. if i keep it on battery charger i can get a surface charge large enough to crank it good, but confused as to why it needs this overcharge to make the starter work for more than one crank. any help?