Fuel injection or aluminum heads

Others know way more than I do but id think if your heads are in good shape, valves all seating properly, id save my money
My 383 was about the same as your engine modification wise..... Plus it was just rebuilt. It was not running right at idle and I knew something was wrong.
One cylinder head had bad intake valves. Its a long story but the end result was I went with Edelbock E street heads. The car ran much better had a better idle and more vacuum.....Performance improved but not day and night wise....
By the time you buy the heads, buy gaskets, change the oil, plus whatever else creeps up you will be looking at 2 grand
maybe changing rear end gears might be looking into