What ever you end up going with, you'll want to be sure that the geometry is pretty close to correct. You could end up losing some of the lift that you would have gained with the 1.6's and have an unstable valve train.....plus, there is a chance the new rockers could hit the springs if you have 1.54" ones. mine did. (Indy ez heads)

If you go to the B3 Racing site it explains it better than I could.....and you'll likely need new pushrods if you go that route.

I use their rocker correction kit currently with 1.6 intakes and I compared lift with and without it, and while I don't recall exactly the difference now, it was significant. (something like .015-.020?) I don't think I'd use the B3 setup with roller cam spring pressures, but on a flat tappet it seems more than stable enough.

Stock type rockers are pretty good geometry wise.