Pre-startup Compression Test Question

[rodneyramjet]

Ok...my inherited 1968 Charger with a 383 is nearing an important milestone.  I took off the gas tank, had it boiled, blew out the fuel lines, replaced the short rubber piece of fuel line, turned it over by hand, pre-oiled it using the "pre-oiler tool on a drill down the distributor shaft" method, shot some more oil into the cylinders through the spark plug holes, and now I am doing pre-startup compression testing.

The car hasn't ran since 1983 but when my stepdad (who was a mechanic) laid it up he shot oil in the cylinders, covered it up nicely, and left it in his garage until the time of his passing a couple months ago. 

Initially all the readings except two were right around 120 psi, but cylinder #5 was only 30 psi the first time, then I shot some more oil in it and turned it over again and it went up to 50 psi. The same thing happened with cylinder #6, first it was about 65 psi, the next try after oil addition was 80 psi.  When I test the other cylinders a second time they also go up.

Should i be concerned enough to delay putting the spark plugs in and trying to get it to fire up?  I'm 99% certain that it ran just fine when he laid it up all those years ago.  Or, should I dig deeper and get this figured out before attempting to fire it up?

Advice please?

[PRH]

IMO, get it running before diving any deeper.
Could be some rings sticking in the pistons, and some heat cycling should loosen things up a bit.

[rodneyramjet]

Excellent, thank you PRH.  I'll post back on the results.