Re-reading this thread, I decided to pull the plugs. From left to right, its #6 to #1. 4-6 are a little black, not much. 1-3 are whitish-tan. Cleaned them up, put them back. Re-dialed the mixture. Fixed the fuel pumping leak in the rear carb. Not a clue how I did it. I pulled the float out, wiped it down. Made sure the needle opened and closed. Cleaned the tan/brown varnish stuff off the bottom of the bowl. Car idles at 1200. Drops to 500 when placed in drive. And ..... we're back to hesitation/sputtering under acceleration load, and can't make it up an incline in the neighborhood. WTF??? 

I was having a blast flying down the road earlier. What the heck went wrong? 

Your front carb was too lean as told by the spark plugs in that photo. If you got the rear to match, both carbs are too lean.

 The hesitation and sputtering is lack of fuel. Now that both carbs appear too lean, given that the mixture screws are at 2 1/2 turns and assuming the needles are installed correctly, I'd suspect the float heights are too low. IF, you're double dog sure sure that everything is correct, you might try using a heavier wt. oil in the carbs. I always ran ATF but Datsun recommended 20wt. if I recall correctly. I"m not an expert on the effects of different wt. oils but everyone has a favorite that seems to work best in their carbs. 

Might check float levels. Pull the domes and Pistons out of the carbs . You should be looking at an empty carb body.
Now counting as you go- back off the mixture nuts(richen) until you see fuel starting to cover the nozzle hole. Compare between the two carbs. They should be pretty close .


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Also sounds like a major vacuum leak


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1 hour ago, madkaw said:

Also sounds like a major vacuum leak


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  Good call. I hadn't considered that. It would explain both carbs in tune and running too lean.