Peck, peck, peck or Knock, Knock, Knock?

Okay, I'm not going to get down yet about my latest purchase ('73 base model EB), but, after owning it for only two days, and it running really nice during that time, when I got in it this morning I had what sounds like a lifter pecking on the passanger side. Of couse it was really loud at first until the oil got up into the heads and softened some, but during my 15 minute commute it still pecked rather loudly especially at the traffic lights. The sound seems to come from the top of the motor, so I don't think it's a wrist pin slapping or anything like that (I checked with the hood open in park).

History on the vehicle: it has not been run regularly (hardly at all) over the past year. Before that, it sat in someone's garage for a couple of years undriven. The PO took it to a local garage to have it tuned up to put on the market. The garage did the following: new battery, voltage regulator, plugs, wires, rebuilt the carb, brake work, oil change, ignition tune up and flushed the radiator/system. I realize that this more than likely due to not being run and having set up for so long, but what can I do to loosen this lifter and PROPERLY avoid further damage to the motor (which seems to run strong and holds 40lbs of oil pressure)? I have heard of people running a bit of tranny fluid in the crank case to loosen things up or using one of the million products on the Auto Zone shelved that promise to rebuild your motor and then refill it with quality oil, but I don't want to do anything without hearing from you guys first.

Thanks for any advise you can provide (I just can't let my wife hear it knocking/pecking this way and think I bought a lemon!

Mac

one thing that you can do is go to advance or autozone and try some stuff called valve medic I believe...I had good luck with that in my EB and after that run a good oil and try the Lucas oil stablizer...I had the same pecking sound and after those two things were tryed it went away

Pull the rocker arms and i'll bet there is alot of wear in the push rod seats and on the push rods themselves and likely the tops of the valves. That style rocker arm was bad about side tipping on the valve causing wear on the valve and valve guides.
You could try some the miracle cures and it may quieten them down enough to pass by the wifes ears. Mine taps sometimes too, and i've run the dog poop out of it trying to blow it up - but no luck. My push rods were wore pretty bad and i replaced them, only costs $10 - $15 I think. It helped but i know the rest of the motor is worn so until i can get my 351W in there, i'll just keep on running it.
You should be ok just running it, tell the wife thats normal becuase gasoline was switched to unleaded after your truck was made. works everytime

What Kind Of Motor Is In It

It has the original 302 with 85k on it. It really runs well, but you can tell it has sat up for a while and just needs to be run. I also never saw ANY smoke coming from the exhaust before this morning (light gray and minimual amounts, but still smoke where I hadn't had any before).