from what i know, these things were designed to give best effect at max revs/full throttle, so I would agree with Pete in getting a good standard tune on your carby. I know a bloke that re-routed all the cooling ducts on an aircooled to the carby and he claims he's getting 3.5 pounds boost

so it might give some benefit.
btw, good job on getting that car running after your truck incident, that thing was rooted.