First off, hello from across the pond!

I've got YT 6333's installed on my L36 heads (Ecotec NA 3.8 V6). I am waiting on the heads to get back from the shop (shipped halfway across the US) and the shop didn't have valve covers to check clearance. There was no description on the Yella Terra website that there would be a need for taller valve covers, but another V6 F-body owner here in the states has the same rockers.

She needed to have custom valve covers installed as the rockers were tapping the covers when being turned by hand. Her valve covers are a 1/2 inch taller, but she thinks 1/4 inch might have sufficed.

What are my options? Does Yella Terra offer a spacer or do I need to go spend $450USD on custom valve covers?

Thanks in advance!

Pics of them installed just to make people happy