You're running an L24 block now? I would definitely use the L28 block with fuel injection. There's no reason you can't trouble shoot fuel injection, it's pretty simple. If you stick with stock, here is your bible: http://www.amazon.com/Bosch-Fuel-Injection-Engine-Management/dp/0837603005/ref=sr_1_6?ie=UTF8&s=books&qid=1197598572&sr=8-6
I use Megasquirt, though.
I think your friend may have been exaggerating on your expected HP numbers, seeing as the stock 77-78 came with the N42/N47 combo + EFI and made around 170bhp/140whp. Where does he expect to pick up another 80hp? Most people aren't willing to spend the money it takes to build a 250hp NA motor, even if we're talking crank hp.