has spark and fuel, wont start.

Seems to me you are chasing your tail, so get down to the basics. All this throwing parts around is confusing the issue.

You need the following for an engine to run:

Compression:

So buy, borrow, or otherwise get a compression gauge and
see what you actually have

Fuel.

You must have fuel. Not fuel that has been in the tank for a year, fresh fuel.
You can substitute starting fluid, or KNOWN fresh fuel sparingly squirted down
the carb throat for testing

Spark:

Must have enough (good hot) spark AT THE END OF THE PLUGS and
AT THE RIGHT TIME So get or make a positive stop out of a spark plug,
and actually check the timing marks. I've posted this here until I'm blue.
Real easy to do, and doesn't take very long.

Then pull no1 plug, and since the plugs are so deep on that engine, device a
piece of hose, wood, etc to reach in and "feel" for compression, or use your
gauge you just bought. AS YOU START to feel compression, rotate the
engine and watch for the marks to come up. This will be no1 "ready to fire"
and you can drop in the dist. You may have to bump it further to get the oil
pump drive lined up, then bring the marks "back up" and adjust the dist so
either the points just opened at about 5-10BTC, or line the reluctor up with
the pickup coil center if using breakerless. IF YOU DO THIS CORRECTLY it
should start as if it had been parked overnight.

Other posts on checking timing marks:

http://www.forabodiesonly.com/mopar/showthread.php?t=121653&highlight=piston+stop

http://www.forabodiesonly.com/mopar/showthread.php?t=112491&highlight=piston+stop&page=2

http://www.forabodiesonly.com/mopar/showthread.php?t=119643&highlight=piston+stop


SPARK PLUGS: Did you ever check the plugs, and CHECK FOR SPARK by
using a removed plug if any question as to condition

If the above steps don't give results, and especially if the compression is low, suspect valve trouble. I don't know the history of the engine, maybe the valves are way out of adjustment, or maybe the cam drive is worn out and has "slipped." So at this point it's probably time to pull the valve cover. Check the valves, you're better off "loose" than too tight. A quick check for valve timing (slipped cam drive) is to bring up the timing marks carefully. On one revolution both no 1 valves will be closed. Rotate the engine 1 turn, bring the marks up again. This time both valves should be "close to" or "at" what is known as "split overlap" which means that one valve is opening, the other closing, and they should be close to equally open. NOTICE that this was an "old standard" that does not work on many modern engines with "smog" camshafts or hot valve grinds, because nowadays, cam timing does not result in a 'split overlap' condition.

Anyway, if the valve timing doesn't seem reasonable, you probably have the cam a tooth or more off due to wear.