Actually I believe the stock horsepower ratings for a 350 during this time period was only around 150 or so. My guess is that with a stock rebuild and just a mild cam, intake, and carb it would be lucky to have 200 horsepower at the maximum.....but that's just my opinion.
A friend of mine did a stock rebuild on an '83 model 350 and installed the Edelbrock cam and intake and ran a true dual exhaust, while it did run better than stock it didn't run as well as a stock '88 with the fuel injected 350 (rated at around 200 h.p. stock).