[mopar346]

The first and most important question is mileage, as Insidious stated tighting up the top end and blow out the bottom end on an old engine. Since it is a 305 and given the fact (by your disciption) that you aren't experienced in internal diagnosis, I would suggest replacing the engine with a 350 from the get go. It will save you through good money after bad in the end. Even if it is a junk yard or used engine, as long as you can verify the vitals and get a quarantee. Best bet is to buy a quality rebuilt and have at it. If you have the extra money most places will up grade you to cams and tru-roller chains for not too much extra. Performance upgrades really depends on your pocket book and intended purpose of the truck.

As far as learning, you can them take the old engine and do all the disassembly and reassembly you want for fun in your time. If you need it as a core then find you one for cheap. There is a lot to building and engine or doing a real valve job but you gotta start somewhere, we all did.

If you have to fix the 305 then have a skilled ear diagnosis it for you and then replace the minimum.