manifold vaccum for vaccum advance ?'s

i dont know how to do a compression test or a leak down test. This engine is not brand new it was purchased in 2001. But it doesnt have many miles on it. About 25 to 30 thousand miles on it. It was purchased brand new by my dad, and he passed away 2 years ago so i got it and put it in a 91 short bed dodge 4wd truck.
I dont think the rings are shot because when i first start the truck up it doesnt smoke out the exhaust... yesterday was the first time i have ever seen it smoke out the exhaust. I was in second gear and reved it up to about 4500 to 4700 rpm and backed off the throttle and i seen the smoke come flying out the drivers side exhaust pipe, light blue smoke.
But i have fired it up and shut it off fired it up shut it off a few times watching the exhaust pipe and i never see any smoke come out of the exhaust when i fire it up. So i'm thinking the rings might be ok. I think its the valve guides that are letting all the oil blow by when i am on it good and let of the gas. I was just thinking if its time for a valve guide job then i might as well just get a new set of cylinder heads. I have been looking at the iron ram heads from hughes. Completley assembled and ready to go i think they are only 1000 bucks and they are better then the factory magnum heads. So i have been told anyways.