Technical Weber inlet manifold ID?

I picked up a couple of Italian DCOE Weber carbs, and some side draft manifolds were thrown in. I keep to British cars, these aren't anything I recognize.
There are 3 with no markings, runner lengths are all the same. There's also a single, shorter manifold with the same mounting flange, the casting says 'SISSELL' and 'SWM 45 LC'.
Closest I can figure, they're for a Chevy 6 cyl motor.
Look familiar to anyone?

 

Looks like it's for Chevy 250 292 6 cylinder..apparently Sissell made a head for that 6 cylinder too..

https://mrhotrod6.myshopify.com/pro...292-inline-6-chevrolet?variant=43254183395483

 

Thanks, BP. I can't use them, they're headed for the auction block.

 

Most out there are Clifford’s…… I’d rather have Sus***’s as a choice if wanted a set…

 

Any chance they would work for a Pontiac sprint 6? Would like to have a setup like that on a Sprint! Have an Austin Healey 100-6 project that has a Sprint 6 retrofitted.

 

I knew someone who modified a Pontiac Sprint four barrel intake manifold to use on his Chevy 250, so I imagine that you could go the other direction.