Swapped a xr259hr cam in my 68 c10 with a 5.3. And im having a whistling noise when you rev the motor or are driving down the road it gets louder with rpms. It still does it in neutral. It still does it with the belt removed also. Its been a while since ive had a hotrod or a cam in something so could it be just the hardened valve train noise? I have the sewing machine noise that i was expecting but this is more of a whistle. Thanks for any help.

 

My first guess is a vacuum leak.

 

I hope so. I don really think so because it drives great.

Everything i read on ls1tech is that its a bad cam.

 

Could be the cam eating the cam bearings out the motor.

 

this is the thread from ls1tech and it describes exactly my problem.

https://ls1tech.com/forums/generatio...am-change.html

 

That doesn't sound encouraging... I'd pull that cam out.