I am rebuilding some Holley one barrel carbs to put on my 265 six--I have welded some flanges to the existing intake for these. These carbs are the 1900 series and have the glass float bowl, they also have the 1 5/8 venturi on the base plate. The carb kits fit 52-67 and I have 5 good carbs to work with---the jet sizes go from 61-66 on the carbs I have. I don`t know any specs on these carbs. One engine I am going to run stock with split exhaust,3:50 gears and a T-5 tranny. The other engine will have the head shaved,mild cam and the engine rebuilt , along with the same driveline. What jet size do you recomend for both applications? Would run three carbs if it won`t be to much carburation. Thanks...52er