Opinions
Don't forget...and this may not have anything to do with it, but a LOT of guys don't realize this.....the 1406 is NOT the performance version 600. It is VERY lean. The 1405 is the performance version and the boosters are different. I like Eddy carburetors, but they are generally lean as a whole and the 1406 doubly so. On a 383, I would think it's not enough carburetor. Now whether that's your issue remains to be seen.