Thanks Chevy37!
I'm not sure if i did find exactly the same link that you said but i found very comprehensive material...will do my homework tonight.

If i do have to change the heads on my 305, what should i be looking for and how much should it cost?

Thanks for all the infos you guys!
I learned more in a few hours than spending week-ends in speed-shop talkin to some big-eggoed smart-ass (usually, also big)

Thanks again and let's talk more soon!