starter/68 valiant

Could be cables/ connections, are you sure the battery is good? How was it tested?

Only way to REALLY tell is to either have the starter properly tested, or check both the battery and starter with what is called a "carbon pile" similar to this:

These amount to a (in the day) accurate ammeter and voltmeter, and a great big huge not to mention large variable resistor across the two battery clips.

You put it on the battery, crank it down to a preselected voltage, that is, the less resistance (more current) you crank in, the more it drags down the battery voltage. This one is marked. You count to 10, reset the voltmeter to the mark, and read the ammeter, which tells you how much current the battery can actually output under real world conditions.

For testing the starter, you Crank the starter for a few seconds on a good battery and watch the meter VOLTS reading, which will "pull down" under starter draw. Then you crank the resistor control on the load tester CW until the voltmeter falls to the same reading as the cranking starter gave you. Read the ammeter, and this will tell you if the starter is drawing excessive current.

The one big flaw in the above, is that you have to have some idea whether there is some problem in the engine/ transmission that could cause friction.

If you don't HAVE (or acess to) a load tester, you can get "some" idea by clipping your meter on the engine block, and the starter positive post. If you get less than 10V absolute minimum when the starter is cranking, you either have a weak battery, bad cables, or the starter draws too much.

If you have more than 10V at the starter, and it won't crank well, replace the starter.

If you have 10V or less, check the cables below and or try another battery. SUSPECT bad connections.

The other little tests are checking voltage at both ends of the battery cables to find out if there is voltage drop across them. This of course along with normal "checking" IE are the connections clean and tight?

The check the cables, clip one probe of your meter onto the engine block. Stab the other probe on the battery NEG post --not the clamp -- the post -- and jumper the starter relay to operate the starter. You want the meter on low DC volts, and the lower the reading the better. More than .3V or so is cause for concern, IE inspect, clean terminals, and over .4 you need to really really get serious.

Same on the positive cable. Clip one meter lead directly to the starter large stud, and stab the other into the top of the POS battery post. Same as above, crank the engine, over .3V drop means cable / connections problems.