I rescently purchased an 81 vette 350 5.7 L.
Anyone that has one of these later models knows that the car is great but we got screwed on the HP!
I don't want a choppy cam,I was thinking about vortec heads but not sure if I need to up the pistion comp. ratio. Ideas?  

From the factory, your Vette's motor was rated at 190 HP. UGH!

I'm pretty sure compression ratio on that motor is no higher than 9:1, it might even be 8.5:1.

The heads on the motor now aren't bad, but can definitely be improved upon. For more HP from the L81 in your car, it really depends on how much you want to spend.

If you're on a tight budget, the best thing you can do for a power increase is a cam and intake swap. A good hydraulic roller combined with the correct aftermarket intake (and a fresh carb rebuild or new carb) could probably get you a good 50-60 HP increase since the factory camshaft was pretty anemic.

If you have the money, I'd recommend a complete top end upgrade, cam, aluminum heads, and intake. Something with a smaller chamber than your stock heads to boost compression, a cam matched to those heads and a new aluminum manifold, and you should easily see 75-100 HP. Top that off with an ignition upgrade to make sure everything's firing correctly, and your '81 will be a screamer.

But here's one more thing. Depeding on your car's mileage, the short block might be in need of a rebuild. If that's the case, I'd take a hard look at just buying a new crate motor for your car from GM Perofrmance Parts. Even their base 290 HP crate motor would be a drastic improvement for your Vette, and if you went to somethign like a ZZ4 or ZZ383, your car would instantle have LS-like HP numbers, and woudl be a real screamer capable of keeping up with most C5 and C6 cars.  

That is very insightful information. Thank you!
I will take your advise on the upper build up, and the crate engine sounds like the smartest thing to do. I actually thought about rebuilding the block and going with a higher compression on the pistons. What would you recomend? Also, any clue if my 190 hp screamer has a 4 bolt or is it 2?
I was trying to stay away from the choppy sound of a cam, not that I don't like it, I love it! But, I wanted this car to be my weekend cruiser that my wife and I can enjoy, but wouldn't mind it packing some good horse power when I decide to step on the gas, Make sense? LOL Thanks again...