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.
EXACTLY where Im at, My 434 is a lil warmer then a stock 383. 440 crank, diamond pistons, decent set of rods from Hughes, and a Hughes cam. Im running Isky ductile iron rockers, and everything on this build is very very budget minded but I splurged on pistons, and rods.
