Hey everyone I'm new here and this is what I have:
1975 Dodge D-100 Custom 225 /6, 727 auto, p/s, 3.55 8.25 rear

Here is what has been done so far:
New exhaust manifold and 2 1/4" pipe with single Thrush muffler (all new)
Mopar orange box ecu with Accel super stock coil
New Autolite proffesional series plug wires with NGK ZF5rn long tip plugs
Head milled .053" with new 340 springs, new seals, bronze guides etc.
Distributor recurve by DI
Newly remanufactured Holley 1945 with new fuel pump
Fuel line mod done
Valve adjustment done
Timing set at 12 degrees btdc with no pinging
All new hoses, belts and related gaskets replaced

The truck runs great but I think it still needs some tweaking mainly with the carburetor. It has what seems to be a "bog" like condition at cruising speeds in high gear. I'll be driving along and out of nowhere it feels like someone lightly stabbed the brake pedal one time for about a second. This happens intermittently and in no predictable fashion. My "gut" instinct tells me its jetted too small but I'm not sure. I havent opened the carb up to see what jet it has yet because I wanted to get some expert advice to make sure I'm on the right track with my novice thinking. Also, the plugs all look nice and tan/orange color and by all other accounts the carburetor seems to function smoothly and responds well to adjustment.

By the way, I had an old Holley 1920 on it that I rebuilt and it did the same "bog" condition. I jetted it up from a #57 to a #59 and it made a world of difference in the way it ran and bog condition decreased but didnt go away all together. I replaced the 1920 with a reman 1945 because I couldnt get the 1920 to respond much to adjustment after the rebuild. Also I thought maybe going to a correct year/model carb for the truck would help condition. Thanks in advance for any suggestion you guys may have.

Sam