I'm building a smallblock to drop into my 69 chevy c10, what i am wondering is in that motor im using a hydraulic cam nothing fancy and stock 86 to 95 heads that i worked over. ive got a set of roller rockers that i want to use, can i put them on with out using guide plates or screwin studs?  Or what will happen if i don't use a pushrod guide plate?

you might need a pair of tall valve covers. put em on, let em rock and roll and have fun. no need for guide plates or screw in studs. locks should be used tho.  

It depends on the holes in the heads where the pushrods come through. If the holes are tight to the pushrods, you may be able to run roller rockers without guideplates.

The only way to know for sure is to mock them up. Once you have them installed, if you can wiggle the roller tips of the rockers from side to side enough to interfere with the locks or retainers, you definitely need guideplates.  It's best to have the roller tip as centered on the valve stem tip as possible, to reduce valve guide (and valve guide seal) wear.