My motor is cranking but not starting. I have things grounded. I'm trying from a charged 12.6 volts in the battery. If I try starting just a couple of times I'm noticing that the positive battery cable is getting pretty hot. What could be causing that?

it's hot because of constant heavy load from cranking, or a bad connection at the battery post - clean both posts.

it's not staring because;

no fuel in carb.

no spark at plugs due to;

broken wire, dist not working properly, bad or weak coil.

Battery and cables are new so they are clean. All connections are good and tight. I cranked it just two times this morning for a few seconds each time and the cable still got hot. I'm not putting a heavy load on it.

What gauge is the battery cable? Maybe it's got a bad contact within the cable end.

It's a reproduction cable for 70 B body big block so it's correct gauge. It all looks good on the outside.

The hot spot is the bad connection. Probably where the wire meets the clamp.

Seen lots of aftermarket cables with poor connection at the clamp. New or not.
2 seconds of cranking shouldn't get the cable warm, let alone hot.

I noticed the other day that the cable got hot when I was trying to start it. So this morning I just wanted to see if it got hot without putting a lot of load on it. So I only cranked it twice for about 3 or 4 seconds each time and it still got hot.

That would be a bad cable.

Take it off, check the resistance with an ohm meter. Try another cable.

High starter draw?

Robert

For sure one of your cables are bad.

I'd think a good/charged battery would be higher than 12.6V. what is the cranking voltage?

First thing I would do is check to see what the starter draw is. If the complete cable gets hot it sounds like to much starter draw which will make the complete cable hot. If it has high resistance somewhere like even a dirty connection at the battery cable end where it goes on the battery then it would only be real hot at that point of high resistance. The complete cable would not be hot. I would check starter draw before I did anything else. And also you can do voltage drop test to see if it has a bad connection in the circuit and if it does you can trace down where with voltage drop test. But the whole cable getting hot sounds like to may amps going through the circuit and a starter draw test will let you know where that stands at. Just be sure the battery is fully charged when doing a starter draw test as a weak battery can give false readings. Good luck , Ron