Anyway to fix this without driving 150 miles to a shop?

 

What are you asking about? The gunk needs to be cleaned off, then resurface by using the post apocalyptic method Ora shop.

A valve seat has popped out.

ouch you could try heating up the head in the oven and then keeping it hot with a torch while you atempt to reseat the valve seat you would also need to freeze the valve seat before trying you want the aluminum to be exspanded as much as possable and the seat as small as it can get so you dont enlarge the hole it should almost drop in with just a light tap on he seat you would need to work fast to keep the hot parts hot and the cold part cold the problem would be geting the seat true enuff for the valve to seat unless you have a valve grinding tool and realy like laping valves and after all that the chances of it staying in place arent all that great unless your in a pinch and realy need the car up and running i would get a new head or send it out and have some one who dose that kind of stuff fix it for you the one time i had i happen to me on my vw bus i replaced the head and had it machined to match the other one it was cheap back i the day good luck

I'll give you my wifes phone number.  You can prime her with an explanation as to why there is a head in her oven.   

 

Meh, I just wanted to keep it as a spare head.  Wonder why it fell out...

lol no thank you i have enuff trouble with the women in my life to deal with anyone elses you asked if it could be done yes it can but results will very you could also use a barbaque or a fire place or fire pit or what ever it just needs to heat the head evenly but i dont think its worth the effert

Yeah, I wont try it.  Doesnt sound like good odds.  Thanks for the input.

seeing as how its a exauhst valve my guess would be running hard uphill full out under a slight lean running condition ether or or both would couse localized heat in the exaust hot enuff to drop a seat im also guessing thats a driver side head that gets slightly less coolant flow but im just guessing

 im also guessing thats a driver side head that gets slightly less coolant flow but im just guessing

 

 

Bingo!  It was a donor car I knew nothing about.  Just scabbing engine parts.

Ah,  I couldn't see it on mobile.  Whatever caused it to fall out, I wouldn't trust just putting it back in.  I've never seen one do that.