I’m looking for a 36 or 37mm chronograph case for a vk63 project.
Can anyone point me in the right direction?

I can’t see any on eBay or Ali.

In the late 1960s or early 70s I had a Bulua chronograph. It had a black and gold reverse panda dial in a cushion or tonneau shaped, brushed gold-plated case with two rectangular pushers. I have no idea what movement was in it as I was more interested in playing on my bike at the time. I bought it from a large watch supermarket in Lucerne, IIRC.
Bulova and Buler were well-known brands then, and I assume the similarity in name was deliberate.
I over-wound it and it sat unused in a cupboard for many years before I lost it 30 or more years ago during a house move.

I’ve googled the brand Bulua many times over the years with no results. Don’t suppose you’ve heard it?

Cheers