If you already have 1.5 rockers, use them. There isn’t enough power there to bother with.
Even if you don’t have rockers, you are better off calling Mancini and buying his replacement 273 rockers.
Using any roller tip rocker will almost always (99% of the time) require correcting the geometry. Please don’t be the guy who bolts on rockers and just skips correcting geometry.
Que everyone who will say “I run roller rockers and I didn’t check or fix my geometry and my 273 2 barrel runs 9.30’s at 140 plus MPH on 7 inch wide BFG’s. With exhaust manifolds.