Valve fell out - Body Glove Dry Snorkel Purge Exhaust Valve Splashguard

Burned intake valve, out of time, excessive carbon on the valves.... check timing first then go inside the engine for burned valves.

Check the hoses to see if each hose is warm, usually 1 is warmer than the other, that enter the heater core from the engine.
If both are warm issue is inside vehicle, possible vacuum operated valve for venting or a cable, sometimes items drop down from dash, like toys, pencils, etc that could stop the action of the vents that adjust heat.
If 1 is cold then look for a valve possibly inside engine compartment on one of the heater hose runs, either vacuum line fell off, cable fell off or valve could be defective if no heat passes.
If no valve, then chances are the heater core itself is clogged and needs to be replaced.
This is all assuming that you have proper coolant level, the thermostat is functioning correctly, and your water pump is working, those should be verified as well when inspecting your heating issue.

Put the spring in first ,then the valve and give it a 1/4 twist .

Hi, had it been sitting some time unused?
Sounds like the valves are stuck in their seats and the rods bent when the motor pushed them with the cam.
You might be lucky and the one that fell in didn't get into the works.
Make sure you fish it out before doing anything else.
I'm guessing it is the typical side valve type motor?
Remove the valve cover (I guess you have already to get the push rod out) and using some sort of lever try and move the valves up against against their springs. Don't bend them with sideways pressure though. If they're stuck some CRC / WD40/oil or similar will help to get them moving. Remove the spark plug and spray CRC etc onto the valve heads inside the cylinder.
Assuming the push rod hasn't contacted anything moving while the motor was being wound over and done more damage, you should be good to go with new push / 2nd hand push rods. Just check there is some clearance between the push rod and the valve stem when each valve is closed.

ya that happens everytime enjoy there not bearings but check ball for pressure ...your answer is torx scews

check for a stuck valve then pull the head and see if the piston moves look to see if the valve seat fell out also look at the head gasket for a missing section

hi

valve clearance(cold)
intake 0.005 to 0.007inch
exhaus 0.007 to 0.009inch

bye

It is possible the reed valve broke.

under the hood is aheater control valve fell both heater hoses make sure they are both warm if not this valve is your problem