Differences in head castings between 96, 97, 98+ prevent using 1.9 rockers?

Trying to get this order in and I'm confused as hell. Wanting to do 1.9 rockers and springs...what is suggested?

ZZP has the 1.9 modified rockers for $274 if I send in mine first. Then the Comp 105 springs. But what I cant figure out is if I can use the stock retainers and locks?

Problem is I read on another site that setup is not recommended for the 96 L67.

Going to eventually install the XP cam and I know that the 1.9's don't work with that but it didn't seem that was what these folks were talking about.

(been to so many damned sites in the last 2 days I cant remember where I read that at...so I'm asking the people I trust)

Modified rockers will work fine on a 96 (TonySmooth89 ran his forever with no problems). I have a set of modified rockers im looking to get off my hands if you want to go that route.

If you're gonna do a cam then you should hold off and put some good roller rockets with the new cam or use the yella Terra or harlan sharpe's with the 1.9 ratio like I did and skip the cam. If I had it to do over I would do the cam change w/good quality roller rockers.

ive got the yella tella 1.9's with 105lb compcam valve springs on my 96 and had no problems.
i think I used the stock retainers and new locks.