My Truck Has Trouble Shifting
 

I just put a rebuilt carb in my 78 silverado and now it wont shift from 1st to 2nd till about 31mph. 2nd to 3rd shifs about 40 after that it runs fine. It was shifting fine prior to the carb change so im assuming I messed up on the linkage somewhere. please help

If it's a 700R4, they T.V. cable hasn't been reinstalled on the carb linkage, or it disconnected at the trans.

if its a 78, i would look at the vac line that leads to the trans. if it not sealed good then the shifting will be off