Still in the ball park. A side-mounted unit on my MG engine will have the option of varying drive speeds to vary boost by simply changing pulleys. A good gauge would be essential here for getting the boost correct in the first place and keeping an eye on this over the life of the blower. If it starts to drop off with wear over the years, just drive the unit a bit faster!

A good exercise in "supercharging on a budget" as original pre-war type blowers are almost impossible to get, and the wait for a new-build replica is 4-5 years. Both are horrendously expensive too.

Pete.