Idler pulley LT1

[Gene D]

1993 LT1. I have my engine(fan) belt off. I checked my idlers. The pulley that is not on the swing arm is very tight.
Parts store says I have to decide on the grooved pulley or the smooth one. original is grooved.
Anyone have any advice on this?

 

[mailmaninvette]

Belt have grooves on both sides ? The original pulley is grooved , new pulley should be grooved . If I still had my 92
I would look at it to be sure.