I just finished building my 383 stroker. IT has 9.7-1 comp ratio. Aluminum 200cc heads and a comp XE274 cam. My friend who builds custom high performance engines for a living helped me out. We installed the engine and broke it in for 20 minutes. Engine fired right up with no problems. Oil pressure is excellent temps are in check. I noticed a knock apparent when you rev it up to about 1500 rpm. Idle you cant hear it. I started to probe around with my stethoscope and found the noise most noticeable at the fuel pump. I put in a different stock pump and the noise was almost totally gone. I put on a new pump (all mechanical BTW) and the knock was back to the same as the first pump which is a Holley 327-11. I pull the pump right off and just ran it with the leftover fuel in the line. Noise is barely there without the pump on it. I have driven the vehicle for about 200 miles here and there and the noise doesnt seem to worsen. It sounds like the knock is with each revolution of the cam. I talked to comp and they said that the cam will have a sewing machine noise to it which mine does but after driving it today it seems that sewing machine noise is more prominent now. I also think its the cam because the knock is only noisey with the pump on it. I cant hear any abnormal noises in the valve covers or from the intake manifold or oil pan but there is some slight noise in timing cover. If a lifter was not rotating would that cause a knock? Would the cam have been wiped out by now? What do you guys think? Sorry for the loong post.

If the noise goes away without the pump maybe you need a new pump pushrod.

I have tried 2 different fuel pump pushrods and there was no difference. I think I will have to pull the intake and have a look at the lifters. I have heard a lot of bad things about these XE cams and am worried that I just got bit.

They are noisey cams I bet its normal noise and your hearing the exhaust valves closeing at a fast rate

I have the Magnum series and they're said to be a little quieter ? I have adjusted rockers and no changes.

I've used three Comp XE cams, an XE262H, an XE268H, and an XS262S solid. None gave me any trouble. The XE262H was in my car for three years and probably 12,000 street miles, and the XE268H is in there now for about a year, probably 4,000 street miles, and about 75 dragstrip passes. No complaints.

If the lifter was not rotating would this cause a knock and would the cam be wiped out by now?

If it is a tick buy the fuel pump, it could be a broken spring in the pump/

SPring looks ok and the pump is my second new one that I have put on. I wouldnt think I have gotten two new crappy pumps out of the box but I guess its possible.

I am runnung that same cam in my 396, it is noisy & does sound like a sewing machine.... But to put your mind at ease, just pull the valve covers & make sure all the push rods are spinning ( engine running of coarse)..

Scott