Happy New Year to all! I have a 4.350" bore early iron mega block. I've been triple checking all clearances and fit of all parts before final assembly.I have measured (actual) clearance at gross valve lift, between the cylinder wall and the exhaust valve and come up with .030" at the closest point.I am fully aware of the shrouding effect it presents.My concern is this an acceptable operational clearance for a 7-7,500 rpm race only moto??. Relieving the top of the cylinder bore is out of the question as it is too close to the top ring territory.It was exactly why I didn't go with a 2.250 intake valve upgrade with Victor heads on this relatively small bore motor. Figured that the shrouding efffect of the bigger valve in that bore size would be an expensive cost with very minimal or no gain.All feedback welcome here. Seems acceptable to me but Imay be missing something here . Thanks in advance. Bill