I'll bet you it is way to fat with that jetting on the Carter carbs, try 398(.098) in the front and 389(.089) in the back with a 16-51 or a 16-98 rod Don't do it in one change, try .003 to .006 diameter size change at a time until it starts to slow down after it goes the fastest or if it is on a dyno when it makes peak power and starts to drop off That jetting suggestion is based on both carbs working on a one to one on the the linkage, not progressive linkage.EDIT. BTW, the fat jetting your trying probally will work on the Eddy carbs, maybe even on the Carter smog carbs but not on the competion series 750,IMO