can you throw 305 heads on a 350 bored to 383 and if so would it produce enough horsepower to be worth the time

not worth it. If your building a 383 just get some decent heads.

absolutely not
305 heads barely flow well enough for a 305, and are very flow challenged on a 350... on a 383, it would be terrible

Bigger engines need more air to make HP. Not all castings are the same and there are a few good 305 head castings. They're good for bumping up compression but if they can't flow enough air into the engine to make power, higher compression is useless.

Aluminum heads have become very affordable. Buy some good aluminum heads and you can feed the bigger engine plus reduce a bunch of weight. If aluminum heads are not in your budget, a set of 350 Vortec heads will be much better than 305 heads.

For the record, you can't bore a 350 to 383. You have to increase the stroke and bore 0.030" over (unless you do like GMP and use a 3.80" stroke & 4.000" bore).

The LG4/L69/LB9 305 heads with 1.94" intake and 1.50" exhaust valves will flow as well as L98 350 heads. With decent port/bowl clean-up and 1.60" exhaust valves, they'll flow even better. You can support a mild 383 that way.

But, by the time you did all that to 305 heads (especially if you paid somebody to do all the work), you're most of the way to decent aftermarket heads.