Roller Rocker Conversion
 

So i have a 98 ram 1500 with a 5.9 magnum. Im interested in swapping in roller rockers in replacement of the stock rockers, but i have a few questions:

1. Am i going to be able to feel a difference in comparison to the stock rockers?
2. Will I be able to clear 1.7:1 ratio rockers without any valve to piston contact?
3. Will i need to replace valve springs as well? If so, which do you recommend?

The Harland Sharp 1.7:1 rollers are a direct swap from all I've read. No changes needed. They are also good for about 10 ponies extra, also from reading. They are a bit pricey though.
https://m.summitracing.com/parts/csp-s70037

So ALL i would have to do is replace the old rockers with these? No rods, no guideplates, no studs? If yes thatd be great but i would think atleast different rods would be necessary.

These should bolt right in. They mount the same way as the factory rockers, so no studs. Guide plate would be up to you. It's not needed, but it wouldn't hurt either... But you would need hardened push rods to go with it.
I have the 1.6:1 version in my 408 and they are truly as easy pull the old and bolt in the new. From everything I've read about the 1.7:1 version they are the same. Hopefully someone who has them will chime in to confirm this, or straighten me out if I'm wrong.

what are the benefits of putting them on a stock engine ?

Basically, the higher ratio rockers make the cam 'bigger'. More duration at .050 lift, more lift in general, etc. Good for 10hp/tq. On the 'bang for the buck' scale, its right up there. Best part is, you don't have to do anything to the PCM to accommodate them. Just bolt 'em on, and go.

I've heard several times that i need hardened push rods but i cant seem to find then anywhere. Any input on this?

Summit, or Jegs will have 'em.

You don't need hardened push rods, those are only for use with guide plates which you don't have. Get the pedestal type rockers from Harland Sharp.

Scorpion Performance also sells 1.72 rockers that are direct bolt and go. Technically for Ford smallblock but they match up like the HS. 5/16" pedestal, non-adjustable. Benefit is less that they're 0.02 higher ratio and more that they're almost $150 cheaper