HI,
Vortec heads require an intake manifold that has a diffrent bolt hole pattern so check your Edelbrock first to make sure its going to bolt up. Next if you have FI already in place and its in working condition, I would stay with it. FI will get you better gas milage and should yeild a bit more power IMO.
Vortec heads do give a good bit of gain in hp but alot to do when changing over I would read up on em.
follow this link
http://chevyhiperformance.com/techar...148_0208_vort/
good luck,
LOST