Super alloy's ( F2120P) are currently on B/O.
They offered the Competition Plus (F2107P)
Would you do it for a say 500HP N/A build?

What about Manley , I dont think they offer a 5.400 long , But you could use .050 up or down locks to get your spring stack right.
Not much selection for 3/8 stem inconel anymore , most all have gone to 5/16.

Actually I think Liberty Engine Parts has 8 Ferreas in Stock.

I've read issues with Manley.
Buying from Ferrea direct I get a military discount.
I don't mind the wait, just wondering if the CompPlus would be a good choice.

ferrea valve have always out flowed manley on my bench

Yup same valves I use in the AK Racing Powermax heads