Glen-A bit off topic here but I did find a small issue with the 9377 you tried. It is all better now, not sure how it got that way either IMO go with a three circuit carb...As Monte said I dont think you would be able to tell the difference in the two on the same car once sorted out.
"I am not ashamed to confess I am ignorant of what I do not know."
IMO go with a three circuit carb...As Monte said I dont think you would be able to tell the difference in the two on the same car once sorted out. 
