Very different. We will need some more info on the engine and it's application to make a recommendation on rocker assemblies. There are a bunch of different ones and their quality, application, and price varies widely. But none are cheap, not even the cheap ones.
I use to race a 426 hemi in NHRA stock back in 1974 to 1976. I went through around 4 sets of stock 426 rocker arms looking for the best set, I checked all of them on the same legal camshaft on one side of my motor with light checking springs , I saw between .430 to .530 lift on all of those rockers. Legal was .484 on the intakes and .466 on the exhaust, I think
My message is those stock rocker are not very good on the accuracy of the ratio on them