Engine trouble shooting help needed

[slow car]

Hi i have a 3l ,Webers, 964 cams, 9.8;1 comp, headers running MSD programmable 6530 ignit .
Just got the motor running today and it is chuffing (like a steam train) on # 2 popping and spluttering up through the Weber at #2.
I have compression tested #2 and it is showing 125psi (cranking)any ideas what it could be?
The motor has just have work done on # 2 ie valves, new piston,rings,2nd hand head.as a piece of steel when through.
I have just fitted the MSD could that give me these symptoms?
Thanks John

[callard]

#2 idle air bleed plugged.

[Bob Kontak]

Not an expert, but shouldn't the engine take a little bit of time to seat the rings? I would think the carbs or MSD have nothing to do with the mechanical compression as you can get a reading without these parts on the car.

Did you take a reading from any other cylinders?