The ‘coolant leak’ that wasn’t: AC condensate

Since the first start I tracked down what I thought was a coolant leak, but turned out to just be the AC condenser drain. Of course I had the manifold off looking behind the engine and found I had left the vacuum line off the map sensor back there, so not a total loss on work.

• Changed the oil to clean up any debris, but zero milkshake.
• Installed the 36# injectors with the GTP injector data from the hp tuners forum- started right up and idled great.
• Installed a ported MAF housing. 
• Finished up the SE header install and midpipe
• Run to temp multiple times to burp the coolant fully
• Some other misc stuff like putting the washer tank back in and ‘carpet’ to be scca max2 compliant

So Monday I had an appointment to take it to Speed Inc to update the tune. Car felt really good initially. The whole thing felt freer than it did previously. No major drivability issues. Kept RPMs under 3k, low load. Part way there I start hearing ticking. I drive for a moment wondering if I’m hearing things and it’s getting louder so I pull over thinking maybe I didn’t do the rocker torque as well as I thought I did. I uber home and come back with my suv and tools. Out in the parking lot I retorque all the rockers. Nothing major off. maybe a couple slipped less than 1/8 a turn. Pushrods feel tight and without play. Put it back together and it’s still making the noise. Sounds like it’s the passenger side. Varies a bit with RPM but not strictly 1:1. Enough to call a tow which takes over 4 hours to show up. 

I’m really really really hoping something didn’t fall in from the manifold that was precariously perched in it. The car ran quite awhile at idle and revving in the garage so it’s not something that was in there from the start. It developed over the course of a few miles drive.  I’ll probably get a chance to look at it this weekend, but any guesses on the mystery noise? Could be a loose o2 that backed out and rattled loose? Maybe it’s the SE exhaust system with its excessive amount of clamps that started hitting something with movement and heat? I had someone suggest detonation, but it seems unlikely at low rpm and low load. The heads should make very little difference under 4k rpm or so.