'65 Barracuda FS factory sway bar bushing replacement

I think your bar is similar to my '68. In my opinion, your mistake is in finishing the bar first before install. My way= clean parts, install bracket only over bar, then with lots of lube work the rubber down the bar into position. Now work bracket over rubber, no cutting. Now you may clean the bar and paint. Never split the bushing, you will be sorry later.