He did back them up with facts and personal experience...unless he was lying of coarse...that's what you asked him....share his experience that he based his opinion on.
I wasn't bashing or promoting. I wouldn't be afraid to use them on something with a small spring...I wish I could find it, but there was a seller/engine guy that advertises on ebay that did a pretty detailed write up on them...they built a set and put them on a chevelle they had with a BBC and then dynoes it. He went into a lot of detail about them and gave his OPINION based on what he saw when he did the heads...best I remember his only big complaint was he didn't think the casting was thick enough if they were cut for big springs....What sort of spring preasure are you running, how long have you owned the heads and how do you like the heads so far?
In regards to the ProComp bbc heads that I have personally worked on, half were outright unacceptable, and returned. Of the sets that were kept, most needed considerable rework. This includes valve seats that were up to .025" off center of the valve guide. Also heads that had varying seat depth (stem height). Several heads needed seats replaced due to excessive depth and seat contact area too wide. Most of the time, the machined dimensions were consist from cylinder to cylinder in the same head, but varied too much as a set.