This is not related to Blakely car but one day might come in usefull for others running turbos. On my Bantam boost is controlled using an Impco TC" control valve and did not wrok properlly (at all). After wititing Impco and searching the net for months I finally came up with this:
On my car the vent valve was plugged exlanning the valve did not work propelly. I will be trying this solution next weekend.