You might have better luck lowering the price. The 305 is a fine motor, but very few want to replace it without upgrading to the 350. Even 350s are free these days. I (literally) have four 350s that I got for free from the paper, two of which are 4-bolt mains that run.
You might also let us know its condition; mileage, running or not, smoking, leaking... if its a perfect engine that someone can use to get going, it might be worth a couple hundred to them but all we know now is that its a lump of iron
