So my head rebuilder wants to use Ferrea valves. I've read several instances where the Ferrea springs and retainers make contact with the rollers and cause issues. Can I use OEM AP2 springs and retainers with Ferrea valves? The head will be getting a port and polish and valve job.
Thanks

 

I'm running factory AP1 intake springs all around with Ferrea valves and ti retainers.

 

Perfect. Thanks. Are you using oversize valves?

 

+0.5mm

 

You can run different valves/springs but you really should keep your retainers and keepers of the same company.