I got a Vista-Pro replacement rad from Rock Auto when my 01 started leaking. I don't think they make all-aluminum for this application because you have oil cooler lines going thru the left side and trans cooler lines going through the right side.
*EDIT* They DO make an all-aluminum radiator that fits a 94 1500 burb, its $929 at
Summit Racing. :E Now I remember why I didn't get one....
If you plan on keeping the truck now is a good time to replace all the hoses, t-stat, and rad cap. On the 01 the plastic overflow tank is pressurized as part of the system and ages out just like the radiator does, worth checking on your 94.