Cam/valve clearance

Oversize valves are VERY common in these engines.
It would concern me that he has never seen any.

Hello, yes he degrees the cams. Thanks

He has built and seen many engines with the oversized intake valves, 37.5mm . This is first engine he has seen with the oversized exhaust valves. 31mm

You may have the wrong set, (not size) of exhaust valves, for the head. This link may help. kzzone.com/valves.html

No, the valves are correct. They are Ape 31mm stainless steel. My engine builder just text me and said he has solved the problem. I will post what he tells me.. Thanks for all the input and help from everyone . I really enjoy reading this forum and glad I joined as a member. Ride long and free. !

36 inlet and 31 exhaust is the most common pairing or oversizes fitted .
This is mainly done to reclaim valve stem height by utilising the unworn part of the valve seat rather than for a performance advantage.
Rarely is one done without the other on a top end upgrade but a larger exhaust is in turbo applications or where the exhaust seats have sunk due the increased heat and wear they suffer.
37.5 intake is not normally seen on its own without an oversize exhaust.
What your builder is saying does not ring true, if he's been building these for 40 years he must have seen an oversize exhaust unless its just his own stock motors he's been maintaining.
If he's that experienced you would not be having the issues you are asking advice about.

Glad that he figured it out. Good luck to you. Keep the throttle open and the rubber down.

I'll make this really simple. A good, competent engine builder would figure out and fix the problem without ever telling his / her customer there was a problem let alone have that customer try and find solutions for them. I've come across lots of issues building engines that I simply fixed and never told or asked the customer for help. After all the customer is paying the professional for their experience and abilities.

I remember reading with the 3X cams and larger the head and valve cover has to be relieved to allow the higher lift cams to rotate.
Steve