The question seems simple enough, but the answer is not.
Put in really simple terms, the way to "more" HP in yer natcho engine is through either increasing its cubic capacity, or raising its compression, and ideally both. And thats assuming it already breathes well and has effective fuel and ignition systems that will support high RPM.
However, making more HP puts more strain on components in the engine. The Pinto's known weakness is its rods, and the next weakest bit would be pistons as far as I know. The block and crank can take a good deal of punishment as is, but if you want to up the compression then rev its nuts off, you will need better rods n pistons. Other things to consider would be ARP fasteners to hold everything together, and high quality bearings, etc. You could also consider a high volume baffled sump, and some snazzy synthetic oil, which I assume the engine builder should know about when they measure tolerances, etc.
The thing that makes it interesting, is that its all up to you, and what you want the engine to do. Are you looking for something fun, or completely crazy? Do you build with stock parts and respect the engines limits, or do you peel your wallet inside out to build something wild? And if so.. What are your diff and gearbox plans lol? And how big are yer brakes?
If it were my engine, and considering that its already had a let go, I would probably be building for reliability this time round. let's face it, a running escort that can't eat silvia's at the lights is better than a broken one in the garage.
If you want to pwn turbo's and V8's.. Buy a bike. [:x)] Mine is old & stock, cost me 5 grand, and pulls a 12.67 quater in almost any conditions lol. I love watching them try

.
Just my thoughts dude.....