Propeller bulk head
 

Wanted front and rear propeller bulk heads for 337g.

You might contact McFarlane Aviation. I purchase a rear spinner bulkhead several years ago from them and in my opinion, it was of much better quality than the original Cessna part. The Cessna part is fabricated of stamped and riveted aluminum and the unit I purchased spun and machined.

There's 4 on Ebay
 

There's about 4 on Ebay. Not sure if they're the part number you're looking for though.

Thanks for reply
 

I will contact them .

Also maybe get your props rebalanced and check your motor mounts.