Head gasket issue '87 ram50, 2.6

[dodgy71]

Have you performed a compression test since it started smoking?

Negative

[FMS88]

Negative

A compression test may not locate the small leak you have, but it will give you baseline readings to work from or suggest there are other fish to fry.
Since the leak is small and if you don't have a cooling system pressure tester, try this test: Warm it up for 5-10 minutes to pressurize the cooling system. Shut off and let cool down completely. Remove the spark plugs and have someone engage the starter for 4-5 revolutions. Watch from a safe angle for coolant ejected from any plug holes, or place a piece of cardboard over all four holes. You should see a spray or find coolant on the cardboard that identifies the cylinder(s) with a coolant leak.
This worked when I had the same problem and symptoms due to a surface flaw between a water jacket and cylinder #4 on the head. Also if looking for another head, avoid one with jet valves. They're very prone to cracking.