i need to buy some hardened push rods cause i heard when you put a higher lift cam in you could bend a rod so i was wondering what the appropriate push rod length and diameter was for a stock lt1...

 

Stock length for LT1 is 7.2

 

is there a particular width or diameter that the pushrod should be.

 

5/16 I believe. Not sure of the wall thickness.
To be completely positive you can buy a pushrod length checker and check it yourself. You would also need to put a light/stock valve spring so you don't damage the pushrod checker. However you can buy them ($35 from LPE part number ends w/ "H"), mark the top of your valve w/ a sharpie, adjust the rocker accordingly and turn the engine over several times, take off the rocker and see what position your roller bearing is on the valve tip throughout the entire sweep of the rocker on the valve tip during opening/closing. There's a thread somewhere around here w/ pics as well as a writeup I think on Comp Cams website.