413 in the 68 barracuda

Interesting, Jim checked clearance with Trick Flow 240 on a 4.250" bore using a 8519pt1 head gasket, intake interference @ .770" and the exhaust retainer hit the seal at@.850" and still didn't hit the wall.
TF heads have 1.76” ex valves vs 1.81” for the ones in the 346 heads and Ede heads.