Rage

Well I just finished checking the last few items that could have contributed to the stud failure. The spring was fine as was the lifter functionality. All tha seems to be left is a stud fatigue failure. Thanks for all the input. New ARP studs now installed.

AIRFOIL292

Just read this,I had the same problem last year.I would be just cruising and hear the pop in the valve cover.The top of the polylock was laying in the head.Long story short broke two.I replaced all the studs with ARP and a little longer.I was only using about 3/8 + of the threads with the poly.I figured I needed more thread into the poly.Problem solved,I broke some lifters also,bottoms shattered.Put all new lifters in also,different manufacture.

Rage

How profetic you should post your experience. I reassembled everything and even though it now runs there is a noticable lifter/valve train noise similar to a solid lifter set up that is not normal for my engine. All I can figure is that the hydraulic roller lifter now will not hold pressure. Maybe that was the original cause of the failure.

I plan to replace the lifters. Anyoen know if there are any issues with this brand for a 496HO engine?
http://www.jegs.com/i/Comp-Cams/249/900-16/10002/-1

FIXX

What is your maximum cam lift? remember as i posted .570 lift max on stock gm lifters..if it were me i would call rm builders and ask bob if he has a set of moral lifters for your engine..as far as im concerned moral is the best lifter money can buy and remember the valve trane is the hart of your engine and takes the most abuse..

Dont know if this was mentioned,did yu check coil bind on the valve springs?

Rage

I thought that you had remembered that the 0.570" max stock GM lifter lift limit did not apply to the newer 496 GM engine? I have had an inguiry into Bob on what is available for my engine from Morel.

Yes, no coil bind issue.

Thanks.