As you suspect, that is not normal.
My first inclination is that the carbs are seriously out of adjustment.
But, make sure the ignition components are in order...or close.

Before I'd go and replace everything though, I would instead clean and regap the spark plugs and points. Clean the contacts on the distibuter cap and rotor. The ignition wires are tough to diagnose visually. You may want to try misting water over them when the car is running and see if there is any arcing to a ground (metal) source. Although the parts will not be new, there is a decent chance they will at least get you going.

Then move on to the carbs. The engine should respond the same way when fiddling with either carb. Hopefully, your carbs are just way out of adjustment. Perhaps the rear is very rich and the front is very lean from your symptoms. Do you know the basics of adjusting them yet? Buy a book, it will probably be easier to follow than only posts here. I'm not saying there is not good information here, just that pictures and text may make it easier to follow.

Don't give up, these cars are pretty simple once you know the basics.




--
Tom - '60 544, '68 220S, '70 145S, '86 745T, '06 Mazda MPV