Icv removal and cleaning

I assume this is the icv, does it just unscrew for cleaning?

Fairly sure thats correct (its been a while since I had my ‘40)
4 bolts and be careful with the gasket.
There’s a procedure to re-set the ISCV once you have it back on the car.

Careful with the bolts - they are famous for shearing off.

From the XJ40 online book (old J-L site):

Just unscrew it. It is the same as the ones on throttle body Chevy engines.