That is really intresting you've cured the running on, though adjusting the butterfly would help that. Hmm, have to have a think why mpg isn't there, mine will only do well on a motorway run, and keeping the speed around 70, over that and it doesn't do as well.

Its really odd, i have an 8 mile trip to work everyday on 3 A roads at 60mph then into a town. Maybe its the way i drive it! or its driving it at 60 mph when its not fully off choke.

I did read some from carb base warping and also manifold warping of 1.7l model, does B200K manifold get warped/bad similar way as in 1.7l model?

I was just thinking, that maybe that manifold warping is what I need to sort for my 360 as I have sorted out carb base warping + all other carb issues as far as I know, still it does take too much air from somewhere.

Water circulation of manifold, what effects it has for fuel economy and if I leave that out does it really has any practical effect at all?