Good to know I use FelPro religiously for anything i need gaskets for.I have used Barr here in the salt pond and they held up as well as any OEM. A set of these is about $1200 brand new. I'm now on year 7 will probably change this fall if I see anything questionable.
The Edelbrock 1409 is a good choice but keep in mind it's probably jetted for the 5.7 so some experimentation will be needed. I have one of those too in case my Quadrajet acts up again.
IIRC Fel/Pro makes marine head gaskets for the 4.3, I used them in my Pre-Vortec, not sure if they are the same for Vortec.
If I go the 4 barrel route that'll be fun, I've never had to rejet and before. I've never messed with 4 barrels either. Is the 1409 a marine carb?