AH64ID

Even with good/clean coolant and proper maintenance the pressure at the back of the block can be excessive at 4K rpms.

I would look into an ultra gauge. No Drill in June for me... and it's AWESOME!!!

Mine is the OEM one in the megacab tailpipe. It's a deeper tone than OEM and a little louder but still pretty quiet. My dad's 06 with the OEM muffler and no cat is louder at some rpm/loads and quieter at others.

I don't see how it would only be a 3rd gen issue when it's a issue based on pressure from rpms of the water pump. It is probably more prevalent in the HPCR or P7100 world due to the rpms capable but still an issue based on rpms/power and not generation, IMHO. That being said I think one of the biggest issues is people romping on it before everything is warm and open.

There are kits that have bungs but they are not required.

DPF "deletes" aren't really needed, just a 04.5-07 4" exhaust and the tuner. Nothing else is required. The exhaust takes care of everything physical.

There was a link above for a sinister EGR delete kit.. For the exhaust order a 4" TBE for a 2005. RaceME or EFI Live are where I would look for tuners. Plan on some time to pull and clean the grid heater as well.

Yes they do, and that may not be a bad way to go... but if a delete is desired after the fact it will take a different tuner.

My dad's truck, 06, is OEM exhaust without the cat. He has a very healthy exhaust note with no drone.. towing or empty.

He very well might and a delete isn't a bad thing.. just pointing out a cheaper option since your description sounds like the truck was never flashed and is an early 08.

Yes

How does he know it is in regen? Software is where I would start. Lots of 6.7's running around the back country and they aren't all parked with full DPF's... at least not since the mid year 08 software update. (That software wasn't out in Nov 07 when I bought my 05 or I might have looked closer at an 08).

Yes, but big differences in programming, APPS, etc... But based on the way 3rd gen's are programmed it is not very likely to be APPS/TPS related.

What year truck? Your sig truck doesn't have an FCA or COV...

Check your exhaust hangars as bad/missing ones are the main culprit for drone on a 4" exhaust.

Deletes are basically black market these days.... really hard to come by. The hard parts are easier to acquire than the software. raceME might ship to the US. EFI Live is another option. Software/tuning must accompany the delete. Does he have the latest software?? Not all 08's came with the software that allowed his style use, but by 09 they did. It is probably worth a check on the software as it's a LOT cheaper than a delete and will keep him from plugging the DPF... unless it is driver style (drive 2 min shut it off, drive 2 min shut it off...). While a deleted truck is better it's not cheap and there generally are not problems with back road use and the latest software.

Did you have any broken piston coolers?

The piston/injector design on the 04.5-07 is a non-reentrant design and some folks are trying to make it re-entrant. Otherwise I am not 100% sure on the desire, maybe it's a stronger spray angle. BBi makes both and I have the 03 version; however, I have 03 style pistons.

My dad's 06 head just came out of the shop and it was 100% good at 123K. When my head was inspected at 93K I ended up with 2 new exhaust valves but they where not bad, but thinner than the shop wanted once they where reground.

50/50... have them do a vacuum check.

As W&F noted they are not TTY bolts, but there is a length guide for them that needs to be checked prior to reinstallation. Studs are always better than bolts but may not be needed. Be sure to lube the crap out of the bolt so the torque is on the threads and not the bolt/head surface.

It has been a couple years so I would guess it is getting proven. Yes those are actual pistons, 03 on the left 04.5 on the right.

The spray angle is matched to the piston bowl shape. The 03-04 spray angle can be used in the 04.5-07 bowl and it seems the results are good. The 04.5-07 nozzle cannot be used in the 03-04 piston thou. Personally I am not 100% sold on it, so my 0.02 is to stick with your OEM spray angle and when the time comes for new injectors use something in the 40-60hp range. Now the 03-04 piston/injector is a much better setup, but time will tell on the 03injector/05 bowl.

Yeah, that's why I said the 2nd

Last week? 102.3% sure it was you, well your truck at least. I thought I saw the 96 in the yard, but we where cruising by at a decent pace. Just checked the text I sent the wife in New Meadows getting coffee and that was as 10:38. Would actually have been closer to 11:15 by the time we passed you. We got to Riggins at 11:36.