So who says the Pontiac 350 doesn't have potential? I know most want a 400 or 455 because these engines have a reputation, but as they get harder and $$harder to find, the 350 is still easy to get and relatively cheap.
It does not take too much to get one to perform if you are willing. This would, in my opinion, be a good engine with a 5-speed to take advantage of the lower gear ratio's coupled with a set of 3.90's or 4.11's out back.
The engine in the article is built around a 350HO which is the 350CI with the #48
big valve heads. What to note is the cut-outs in each side of the block's top bore to provide clearance for the bigger valves - this is factory. Not all 350 blocks will have this, but the scallops can be added by a competent machine shop. From what I have read, and as you can see, the 350 blocks (which I think are the 1968-1970 years) have the scallops on each side whereas the later blocks don't. If you use the smaller 1.66" exhaust valve versus the 1.77" valve, you don't have to have the exhaust scallop for clearance. Again, choose a block/engine that is 1974 or earlier as I have read that they too were made lighter/weaker.
I don't see anything real trick with this build seeing it is aimed as a Super Stock entrant. The key in my opinion is the roller cam which will allow the engine to really breathe, but is certainly not crazy at .512" lift. The rods are the factory cast rods along with the factory crank. The RPM limit of the engine was 6,000 no doubt to the cast rods.
So, the 350 can be made to perform without a lot of trick items and externally, it looks like a 400CI so no one will know the difference except you.