Are you seeing any bubbles in the radiator while its running with the rad. cap off ???
Bad thing about blown head gaskets is they can let water into the cylinder, when you crank the engine over to start that water does not compress, usually it blows out the cylinder wall....!
Then all you can do is sleeve it or get another block..$$$$$$$$$
But if this happens you will have water in the oil and your oil will look like a chocolate milkshake...
If I might ask......What makes you think that your head gasket is "Blown".....?
Pressure washing it probably got moisture inside one or more of the boots around the ignition wires to the plugs.....pull each one off and clean and dry it, replace it. Do the same to the rest of the electrical connections...
Also check for cracked vacuum hoses , it won't take much for a crack to suck air and cause problems... usually the cracks will appear around the ends where the hose connects....just bend it a little a see if it has a crack, if it does, cut it off and put it back on.....if it's real hard and brittle, change it out. Any Auto parts store or hardware has vacuum hose.....
Good luck ! "BH"
Poison spider Evap.Skid/Master craft grab handles/Or-Fab spare tire-can carrier/ Gibson SS Duals/ Q-tec Floor Liners/Hidden Hitch Receiver, AntennaX 7inch, 48" Hi-Lift.
Viet Nam Veteran 69-70, Troop "D" (AIR) 3/4 Cav. ,25th Inf. Div. CUCHI RVN. UH-1H Crew Chief of the "Pinball Wizard" 68-16224. Call Sign "CENTAUR".