Try looking around for some wrote off cars with low miles, I just bought a 95 Camaro with a Tune Port Injection LT1 and only 62,000km's on it for $1900. Not only do I get a great motor with an Overdrive trans but I also have all kinds of useful parts ( rear disc brakes for a 10 bolt ) decent seats for a future project and I will part out the rest of the car and most likely make back at least half my investment.
Sometimes it's worth it but for some they don't have the time or the knowledge working with FI vehicles. If all else fails for $2000 buy a fresh rebuilt 350 for around $1000-1200 and a rebuilt TH350 for anywhere around $800-1000 and your set. Good reliabe 350/350 combo's are the choice for many people.
it depends on what you like?
if you want a hot rod-built for speed,or if your like me and just like to pack the ride full of homies or the ladies and just cruise then keep the straight six!
mine never goes over 7O mph!