So I'm putting together a carbed Vortec 350 for my 85 Bird. Its an automatic with stock stall and 3.08 gears.

From what I have read the LT1 cam is a pretty decent mellow upgrade for these motors. My question is, would it it be worthwhile to snag the LT1 valve springs and retainers and use them instead of the factory springs on the Vortec?

No. They are just typical weenie stock springs, barely adequate when new and GUARANTEED inadequate after any significant use. Better to get NEW stuff, just the entry-level gear from any of the top-line cam mfrs such as Comp, Lunati, Isky, Crane, etc. Avoid GM, stock replacements such as "Z28" springs regardless of how attractive the price seems, and K-Motion.

There is no such thing as "the" LT1 cam. There are about 5 or 6. You want to avoid the B-body one, and get one of the F- or Y-body ones instead. If you go for a used one, pay careful attention to what kind of car it's out of. The better ones are beginning to get scarcer than they once were, but there's still LOTS of the Impala/Roadmaster ones - that you DON'T want - floating around.

You'll probably have to do some work to the Vortec heads' valve guides to keep the retainers from hitting them. Alternatively you could use "beehive" springs instead, as their smaller retainer is good for about an instant extra .050" of clearance.

My buddy did this same build. 350 motor with vortecs and an LT1 cam but not sure of the year. As said above, there are a few varieties and some are better than others.

Definately put in fresh springs in the heads. doesnt have to be anything special to control the lobes on the LT1 cam, just a suitable diameter spring that fits inthe head spring pocket. Comp 981's may work just fine, although I'd like to see a tad bit more pressure.

His motor in an 83 full size shortbed pick up truck ran 13.5's at 99 mph. thats moving pretty good for a big piece of steel. Performer RPM vortec intake and 750 carb, 3500 stall, 3.73 gear. Its a torquey setup with strong power in the midrange

Yeah, I was looking for an early F body LT1 cam, I think with its lift i won't have to worry about the do work to the heads themselves, a couple truck and 4x4 websites seem to confirm this.

Orr89RocZ, that is very encouraging to hear. I was hoping for close to 300 whp. I have a set of hedman long tubes and a dual 2 1/4 exhaust, that are already on the car. My transmission feels pretty solid and I think it was rebuilt or worked on by the previous owner because it has an odd colored pan on it, and the fluid looks brand new.