And, as the article implied but didn't out right state, (if even possible) 300 HP at what RPM? The engines he seems to build I'd assume have a rather broad torque curve with their short duration (he never did state the overlap) cam. Not every Pinto engine should be intended to power Buddy Ingersoll's Pinto.

To start with I would like to say that under normal circumstances, and I’ve stated this earlier in a post, 150 HP seems to be a reasonable goal for hot rodding a 2.0 Pinto.
However, the quest for finding more horsepower in a Pinto didn’t stop after the appearance of David Vizard’s book, which was written in 1983.
If you look at that date, that is well before Cosworth churned out some 39.000 2.0 Pinto based engines , with hp figures between 204 and 220. OK, these are turbo’s, but perfectly streetable engines.
If you read Des Hammill’s book “how to power tune Ford SOHC 4-cylinder Pinto & Cosworth DOHC engines”, which was revised and updated several times until well in the nineties, you see that a lot of Cosworth technology and parts are finding their way into normal Pinto engines.
A Pinto block with a standard Cosworth DOHC head would reach between 150 and 170 HP before any serious tuning work is done, so it goes up from there.
On the other hand, primarily in Scandinavia, people kept pushing the SOHC’s to new heights, some went for big turbo’s on crude engines, but fuel injected, and controlled by sophisticated software.
 And there were still people developing the NA (naturally aspirated) SOHC’s, see the Finnish example from 2008 in the images, mind you those power figures are in KW’s, that’s 240 hp.
New Cosworth YB heads are available in the UK, also YB aluminum engine blocks, so only your wallet will be stopping you from going over 200 hp, add turbo and go beyond 300 hp.
I don’t think it’s fair to put a definite ceiling on an engines maximum possibilities based on a book (a very good one)  written 32 years ago, and very capable mechanics (flow bench wizards) who won’t touch injection systems and ECU software.
For the moment I’m still happy with my 115 hp 2.0 Pinto EFI and T9 5-speed.