Sell the Ford and do the na-t. (if your engine's getting kinda old, like over 100K, do a rebuild first)
Then fine-tune the shiznit out of it and you'll be looking at 500+ horses.
You'll end up saving money over the ge-gte conversion, but make sure you get everything you need and every possible precaussion you can get.
With a turbo, you want to make sure that no matter what happens, you don't blow your newly rebuilt engine within the first few weeks.
Oh yeah......F-Max!