CWYates,
350 Heads on 305 would reduce compression significantly, and you would lose power. While flow would slightly increase (305 heads aren't bad!), it wouldn't be enough to make up for the lost compression.
There's a website dedicated to the CrossFire injection, and the company has LOTS of goodies. We're building a 383 for an '84 Corvette right now, making over 500 HP for the street, using the CrossFire. I can't recall the name (I wouldn't be allowed to post it anyway...), but do a search and you'll find it.
A good friend has an '86 IROC with a TPI 305, and it makes over 400 horsepower. A real "sleeper"!
Jim