Blow head gasket?

Hi all. Been trolling these forums since I bought my 97 4.0 automatic 4x4 last year. I love this truck but it's recently feeling it's age and 170k. I bought it because the frame wasn't rusted through (central pa moutain winters are not kind to frames out here) and it ran decent.
First it decided it was gonna take its time starting. It would start but chug at it for a minute. Ran great. Then it wouldn't start hot, I would have to let it sit for hours before it would turn over. Still ran great. Father in law insisted it was the starter, so we changed that. Drive it home after putting in the new starter and it just would start at all, even cold.
Replaced the battery. Noticed the overflow tank for coolant was bone dry, added coolant (that came with the car, probably should have told me something). Never over heats. Ever.
Starts every time now! But I runs like garbage. Engine light. P0304 code. I suspect head gasket because of the cylinder misfire and disappearing coolant... Plus the nice white smoke when the truck is first started...But I'm not all the mechanically experienced and admittedly know nothing about cars.
Just trying to confirm my suspicions, or If not that, get another idea of where to start.
If it is the head gasket, im assuming pulling another engine would be more cost efficient at this point.
Thanks for reading

Night time exhaust video. The truck has just been parked a hour before so it's not just exhaust condensation.

If the overflow tank or any of the hoses aren't leaking, then yes, it sounds like either a blown head gasket or a cracked head, to me.
If you can procure a low mileage engine for not too much $$$, that would probably be your best bet (assuming the replacement engine is problem free).


Dean

From what I've heard, if the exhaust smokes white once warmed up, it's blown. Another way is to top off the radiator, start is up and look for a consistent bubbling through the hold where the cap goes. I guess the proper way would be to get a test kit.

While driving my 2.3over heated and quit running so pulled it home , it turns over and makes sounds like timing belt slipped so I replaced the belt,water pump& tensioner ! Now all timing marks are wright but still when turned over it still makes that noise like timing is off ,then I found oil on the block , so checked dip stick 3 it's low ! And I just changed oil in it .now thinking blown or cracked head ? When turning motor over by hand there is no compression at all