bad cam bearings?

i just had my 88 renix rebuilt has only about 3000 miles on it.i took a road trip for the first time since the rebuild,and was the first time it was at highway speed for any length of time.by the time i got home it was making a loud ticking sound.i took it back to the motor shop and they said the cam bearings went bad,and they are known for it.he said he would eat the labor but i had to pay for parts,and for the motor getting pulled and put back.i'm just wondering if they really have trouble or if its his way of getting out of paying?he said there is an aftermarket bearing that addresses the problem?i got my rebuild kit from clifford performance and i cant see them selling a part that is known for going bad in a performance app.when there is a part thats better.i was just wondering what you guys have to say about it. thanks

Never seen a cam bearing go bad or make a clicking sound.