273 rocker arms

All good info guys..tx.My engine is built and i made no modifications to the new stock shafts or rocker arms.A friend told me that i will be sorry and the modifications are necessary so thought i would ask on the forum.
As you know... i try to use logic and question most everything.
Now....who have used stock 273 adjustable rockers with standard shafts and how did they perform for you?