Can i take a GM Performance Parts 330hp 350 and use the holley 670tbi and ecm as a stock 305

 

I don't see that as a viable option but yes, you could physically run the 330ho motor with the stock 305 eprom. I don't recommend it but if you set base timing up correctly (at least 8 degrees) and tune the fuel with a vacuum referenced FPR then yeah, it'll run alright. The holley FPR can be made referenced with very littley work. There is a hole that needs to be filled with a screw and then ground off, then there is another hole on the side that just needs a poss pressed in for the vacuum line. The only problem is that you're going to see a BIG difference in pressure when you hook up the vacuum. It's just not going to run very well. Burn your own eproms, chant this with me. Again and again.
For less than $100 you can burn your own eproms and if that's not enough, just go carb. At least with a carb you can get other people to help you tune it in PERSON (hint hint, don't buy online eproms).