97 Club car belt slipping

[Mdslawn85]

Hey everyone I just purchased a buddy of mines 97 club car. He picked it up from the shop right before I bought the cart and had a lot of new parts installed on the cart. Upgraded to a 350 motor new driven clutch new belt. Well at first it would run fine on flat ground but going up a hill it would come to a stop and squeal . I took it to the club car dealership and they said that whoever installed the motor put some spacers behind the motor to space it forward( the ones needed for a 290 motor) they said that the clutches looked fine and the belt was fine. Anyway they said that they would have to take the motor out or move it forward to get the spacers out that they were not needed for the 350 motor. They said the drive belt was extremely too tight. Instead of letting them do the work. I took it back to the shop who installed the motor which is an ezgo dealer and told them the information since my buddy had spent over 2000 getting all the new motor and parts installed. . A week later I called to follow up and see what they found out and they said that they had installed a new drive clutch and a new belt that was my problem 560 dollars. I would have been fine with that if it would have fixed my problem. The cart will still Just not climb a hill like I think it's supposed to. It doesn't really squeal like it used to but feels like it has no torque and you can let off of the throttle and it feels like the belt will grab a little bit better. Not really sure what is going on . I also got in some very light mud in ruts and could not even get the cart to turn the tires. Any help would be much appreciated .