[Woodz428]

The bread and butter FE's sometimes shared a head casting, they so share valve sizes. Some 428s had those type heads, then some were the CJ which are very similar to early 427 heads (bigger valves/ports). Different heads won't change engine size, although sometimes compression, 390s and 428s (as well as several other size FEs) all share basic castings and that's why a different head will fit. The reference to 390 heads was probably more a statement that it lacked the nice CJ heads than it had another set of heads on it since the straight up 428 probably had, what are the same as ,390 heads.