can i remove my valve springs while heads are still attached in the car?if so is there a certain tool besides a regular valve spring compressor that i use?its a 94 lt1

 

Yes and yes.
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Make sure the valves don't fall in the cylinder.

 

The way I have done it is by using an air compressor to allow air pressure in the cylinder to keep the valve seated and stop it from falling back into the cylinder. There are tools available that are designed to compress the spring so you can remove the springs and seals "on-car". The tools can probably be bought at most auto supply stores. Really no big deal to do the job "on-car" as long as you have the proper tools.

 

If You're a bit nervous about using compressed air, You can pull the spark plug and use a piece of rope snaked in through the plug hole to fill the space. Just hand turn the engine until the piston is up and it pushes the rope against the valves. Do this with the rocker arms off the cylinder that You're working on. After You've changed the springs on that cylinder, Reverse the rotation and pull the rope out and move to the next cylinder. P.S. Don't forget to leave enough rope sticking out so You can pull the rope back out of the cylinder.