Well, before you spend any real money on a 305....don't. Get a 302 (Chevy-not Ford), 327, 350, or 400 small block instead. The 305 can make power, but by the time you do it will cost too much and still be less powerful than if you had put the same money in a 350 instead. The bore is too small which limits valve sizes, a crucial problem with only 2 valves per cylinder. To put it in perspective, my 2.4 liter Nissan DOHC KA24DE 4 banger in my 300k mile Frontier has 143hp, or about the same as your LG4. The 240SX version of the same engine has 155hp, or 5 hp more than your 305. It also has a smaller bore and larger stroke, but the 4 valve head means it still has more overall valve area than the 305. So, flow is not restricted, and it makes the same power with less than half the displacement. Pushrod V8's only make sense with a large bore. This is why most popular performance 2 valve pushrod V8's have at least a 4 inch bore. It allows for enough valve area to have good flow on a small block engine.
BTW, "j*" is considered a racial slur and not advisable on an open internet forum. You do not know the nationality or ethnicity of the people you are trying to get information from. I may not be Japanese, but I do not like using such slang.