I was reverting with a 110° lsa on my big block. I know there’s more to it than just the lsa but 109° is suspect in my shade tree mechanic eyes. The oil pressure is another issue so check with a mechanical gauge. It looks like a strong chance that it’s coming back out.

That cam is what comes in GM 96-2000 5.0/5.7 Vortec trucks.

Does it even have any overlap at .050 " ? Doubt it. 196*/206* duration at .050" is tiny. LSA has to be looked at with duration #'s to come up with enough overlap at .050" lobe lift to cause reversion.

Is this a sign of water in the combustion chamber? This is looking down the riser and the little speckles are rust spots.

have you pressure checked the exhaust manifolds&risers?you may have something cracked.

No, but I wish I did when I had the block at the machine shop. There are no visual rust trails other than this riser, the other is just black from exhaust.

I also did a compression test and expected to see a little higher numbers on a new motor. Is it possible I tightened the valves to tight?

Just for fun, had a few minutes, so I ran some #’s.

The above cam has -17* overlap at .050” .

A 209/213 at .050” with 114LSA cam has -17* overlap at .050” also.

Here are some popular performance cams :

A 218/224 at .050” with 112 LSA has -4* overlap at .050” .

A 226/232 at .050” with 112 LSA has +5* overlap at .050”. With 114LSA it has +1* overlap at .050”.

A 236 / 244 at .050 with 112 LSA has +*16 overlap at .050”. With a 114LSA it has +12*. overlap

So basically reversion is a non issue with my motor?

what preload are you using, I presume hydro roller ?

Yes hydraulic roller. I wiggled the push rod up and down while tightening until there was no movement left, then spun it with my fingers while tightening until I could not spin anymore. Once that was done I went a 1/2 turn more.
With #1 at TDC I tightened exhaust 1,3,4,8 and intake 1,2,5,7
With #6 at TDC I tightened exhaust 2,5,6,7 and intake 3,4,6,8

what lifters are you using, on mine, when I feel tension or drag on the push rod I then start the preload to 3/4 to 7/8 turn down, you could be collapsing the plunger if you tighten till you cant spin the push rod, and might be hanging a valve open