I’ll offer this counterpoint to the OP.......

Imo, The parts supplied with the heads are perfectly adequate for the primary buyer these were targeted at.

Used with a .500 lift or less hyd camshaft in an application that won’t need to exceed 5500rpm....... I see no need to replace anything.
I just went through another set last week that are going on a very mild street 440 that will be getting the small summit cam, stock 4bbl intake, stock rockers, stock ex manifolds.
They were less $$ than refurbishing the worn out factory heads.

They have worked out perfectly for the past 4 years on my 68 Charger motor which is very similar to the above post.
Mike