Regular port Commando head clearances

Did they check retainer to guide clearance?
Is the spring coil binding?
Do the pistons have valve reliefs?
Are the pushrods the right length?
Have the heads been cut any, if so how much?
What head gaskets were used, were they thinner if so how much?

If I recall correctly the heads have cast in rocker stands so the rockers should be in the correct location. Did they by chance use a 3/8's pushrod instead of a 5/16? This would close up the clearance a good bit a full lift, and machining the pushrod hole would be necessary. But all this should have been checked in a mock up. Personally the stock rockers are ment for showroom stock engines, if any performance is in mind the rockers should have been changed to aftermarket adjustable ones, and the correct pushrods to fit them. Being mech. or hyd. lifters. Hope this helps and you get it figured out.