Chugging with 4.10s

[85MustGT]

Since I have my 4.10s installed, every now and then, in first gear the car chugs/surges a bit, kind of like a bucking bronco.
To stop it I give it a bit more gas or shift into second.

I put the 23 tooth speedo gear in until I can afford the Speed-cal, next month. Seems like the speedometer is still off a bit. Once calibrated will that help the chugging issue?

 

[stangman]

the speedo gear helps but doesn't correct it at all. but i imagine the chugging is coming from you not giving it enough gas in first when your just kinda rolling along. mine does that with the stock gearing if i get lazy