I bought a set of AeroHead 360 heads. I asked for the hardened exhaust seats. They were #3769974 heads, with 1.60/2.02" stainless valves. The valve seats were not blended into the port much, and the bowl/ports were untouched so I doubt they flowed any better than with the stock valves. No issues with the heads other than the deck-to-quench area was about 0.010" different between the heads. For my "quench" dome KB232 pistons I had to have one head milled 0.040", and the other 0.050", then polish the chambers to equalize the cc's. I also opened up the bowls and did some porting on the heads, also cut the seats for dual valve springs, Opened up the pushrod holes for 1.6:1 rocker arms, and enlarged the head bolt hole where oil comes up to oil the rocker gear because I was using head studs. Here is a pic, sorry about the bad cellphone camera quality and surface rust in the ported head ports (cleaned them out with soap and water.) anyhow, left - after some porting work, right - as delivered from Aerohead.