Not a BB but,I have a 367cuber with a Hughes having about the same specs, and it's about 11" at 700, @930ft elevation. It will idle down to 550 in gear(M/T), with a lot of ignition retard. IDK the vacuum down there,lol.
A 440 would probably pull a lil more vacuum.
I’m getting 8-9” @700rpm. Was getting concerned that I may have a vaccum leak but other than the low vacuum I have no other symptoms. Since the EFI is controlling timing I may bump up the base timing and see what that does.
