22r head gaket?

Ok I posted on 4by cheap on gas.  I have been driving my datsun for gas price reasons being the 2x gas mileage.  But on to the question after a little explaining.

'86 toy reg. cab 22r 5 speed stock cept for 31's.  For those not into toys this means carbed (last year of carb, first of ifs, man what a year to pick).  Like said I am getting no better mpg than when i had my '73 chevy 350 3 on the tree on 35's.  The truck does start and run good but i think lacks on power compared with the 2by 82 datsun that is also 4 cyl. w/5speed.  Both trucks are in the 155k-175k range.  I am beginning to think there is a head gasket problem since this seems to be common on some of these toys.  The temp seems to fluctuate (sp) a bit. A short drive (4 mile) then the truck sets 30 min or so before a open the radiator cap and it is like it has air preasure in it.  I do not have the tools to do a compression check but i may see about borrowing them.  Like said in the other post i am getting about 12mpg.  There is no exchange of fluids so if it where the head gasket it would just be from the cyl. to the water port.  Does this seem as if i am on the right track?  Or could it  just be something as simple as the timing belt or need a valve adjustment.  I have put near 4k miles on this toy since i have had it.

Ok ya'll let me know something.  If i am on the right track and do not feel like doing this myself what would i be looking at for a head gasket, valves obviously have to be done if the head is pulled and a new timing belt installed.  I am an industrial mechanic and can do this if i take my time but alot of people do not understand that there is a difference between a industrial machine and a motor in a truck.

nuff, said thanks in advance.

pop your radiator cap off and start your engine.  Watch for air bubbles in your radiator.  This is a quick way to tell if your head gasket is bad.  

I would still confirm it with a pressure leak down test lacking any other confirmation.

This weekend i will do a compression check and see what i see.  I have not let it get warm enough for the thrermostat to open with the cap off the radiator.  I will see about this wekend also.  I was told by a friend that to get the cover off to change the timing belt you need to loosen the head bolts he thought on one of the 22r motors.  So not knowing when the belt had been changed last I think it may be good to go ahead and do both (head gasket and timing belt).  But I would still like to check and see if I could confirm this is the problem first.  I know if it is then I should be able to look at the gasket once I get it off and see where it was leaking by.  Will let ya'll know next wek what i find.

If the gasket is bad, do not put it back together with having the head check for flatness. Head gaskets do not just blow for no reason. Usually is is because the head has warped some or it was not properly torqued.

When i get to working on it i will check the head and block for straightness.  My son this morning turned my truck turtle, so till I figure out what i wish to do with this I will put the work on hold.  If someone  south of atlanta has a toy that i could put my drivetrain in or a cab to put on my frame they could e-mail me at joemaintenance2@yahoo.com .

You need to have a very serious talk with your son.