Smog legal eh?
I've built a few engines on my own and learned a few things with each build. I've got it to the point where I'm not wasting money on [censored] that doesn't work anymore. Good power from an engine that'll pass smog is easy to build... but it ain't cheap. Since you said you want to freshen it up you'll be yanking it out so you might as well go for the gold.
You'll have to step up to larger injectors and a fuel pump that can flow enough juice to feed them. Then you'll have to consider a larger throttle body to let more air in... and a manifold, then heads, headers... and on and on.
Stroker kits will really add a butt-load of HP and TORQUE. Even without the stroker kit, a set of quality heads, a properly matched CAM and new injectors/pump, your EFI motor could make 400HP at the flywheel easily and reliably and run on PEMEX if it has to. My 351w is making about 400hp and cost me about $2000 grand to build - did all the work myself. CARB = CHEAPER ... EFI = EXPENSIVE
Beware - It all adds up fast on an EFI motor man... these are retail SummitRacing type prices - actual prices would bbe lower if you shopped it out or found a friend... -
24lb or 30lb Injectors for a set of 8 = $200
Ford Motorsports Fuel Pump = $125-150
Edelbrock Throttle Body = $285
TrickFlow or Edelbrock Intake Manifold = $550-ish
Piston and Ring Kit = $250-300
Heads = $1000
Pushrods (cheap insurance) - $50
Machine work = $500 to ?????
Cam = $200-300
Complete ARP Fastener Kit = $175
Total = $3500-ish - no labor
Stroker Kit = $1000-1500 - subtract previous $$$ for pistons
Total = 4500-ish - no labor
Your stock computer can be retained to make good power, that's the beauty of the MASS AIR FLOW setup. You either need a sampling tube or a slight EEC tweak. Geek engine stuff <---- Or you can ditch it and buy an add-on system that plugs into existing stuff and lets you tweak the settings to match your new displacement and airflow.
I'm sure you'll have no trouble finding a shop to do all the machine work - go for the "works" package.
Aloha