Ive replayed carb, plugs, wires, points, dist., everything I can think of and still it will not crank, it will for about a second the shut down. There are not loose wires.

 

Check the battery voltage or just try jump starting it and see if that works. If it jump starts you have a bad battery.

If battery is good check for voltage at the starter relay "S" terminal wire when the key is turned to start. If you don't have voltage at the terminal then there is a circuit in the ignition system preventing it from starting. That would normally be a safety circuit like tranny neutral switch or clutch pedal switch.

If you do have 12v at the "s" terminal wire then test your solenoid. A simple way to see if your relay is working is when you turn the key you should hear the relay click on or have someone turn the key and feel the relay and try to feel the click. If it doesn't click then bypass the relay. A simple way would be to use 2 screwdrivers. Put a screwdriver on each of the big terminals on the relay then touch the metal part of the screwdrivers together. Yes it will make a big spark and it may surprise you because the starter will turn and try to start the car. Just make sure it's out of gear and your key is off.

If your starter does turn over when you bypass the starter relay then you will know your starter relay is bad.

If you hear or feel your relay click once every time you turn the key to start then test your starter.

To test your starter use jumper cables and put the cables on a good battery then the other end put the black cable on a good ground such as the starter housing. The red cable put it at the big terminal where the cable from the relay goes to. If the starter is good it will turn over. If nothing happens then the starter is bad.

Hope this helps.

 

A V6 1970 model would be very rare indeed...

 

That would be a Inline 6 or 'I6'.
Check all your grounds and cables. Grounds should be to unpainted metal, you can put some bearing grease on them to avoid rust but you need bare metal contact. Check your battery cables, they should be pliable and hold shape if bent, not rubbery or stiff as they may be melted or corroded internally. You need clean contacts at the battery terminals also.
I would first take your batterry into any parts store and have them put a deep charge on it (up to 24hrs.) and then have them load test it and recharge if good, it's free. This will eliminate the battery as your problem. As mentioned do you get a clicking at the solenoid or any other sound before it stops?
Pics of your engine bay, alt./battery/ solenoid wiring area would help as we may spot an issue.
Jon