I bought my 71 GTX when I was 17 and it took almost 15 years to finish it because of school, work, etc, etc...

If there is nothing wrong with your 383, then do a basic rebuild and enjoy it. Once other "life" things come along, you could easily lose interest. I'm 35, been there, done that.

I HIGHLY recommend you difine what your real goal here is. A nice driver, fun street car that you can take anywhere or a drag car.

If you work with a stock 383 shortblock that gives you true 9-10:1 compression (decking required) and bolt on a good set of heads that are worked (maybe some Stealths), you'll have all the power you need and still have $$ left to work on the rest of the car. You can get it in the 13's pretty easily with the right choice of parts and still maintaining stock appearance and drivebility with, say a 3.23 or 3.55 gear.

Dropping $5K in a motor just to keep up with the big dogs isn't really a good idea if you intend to sell it in the near future.

The 346 heads have hardened seats from the factory, saving you the extra coin on head work. Drop in some quality oversized valves and springs to match your cam will be a good decision. Maybe some home porting with some templates. Or for around 1000 bucks you could be in with some Stealth heads. 440 source says the heads should be taken to a shop for inspection.