First, double-check your firing order. Make sure you don't have a couple crossed.
Mine did that for a while, too. Rebuilt the carb, checked everything, found a bent pushrod and fixed that, still didn't run well. I'm embarrassed to say, I found the fuel shut-off valve close under the cab. Did it myself during a previous job and forgot to open it. A small trickle of fuel was getting through, enough to start and run, but no power.
Sometimes it's the silly little things...
Current fleet (subject to change w/o notice) \'49 GMC 3/4-Ton , 60 Austin Healey Frog-eye Sprite (some assembly required), 2011 Dodge Avenger, 2015 Jeep Cherokee. No, they don't all run. My other ride is a (B737)no, (B767)no, A320.... Update... was Embraer E190, now Boeing B787. Knowledge is a wonderful thing, but ignorance means you don't know you can't do something.
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