Head Studs
PHP has done some cylinder pressure testing, and Bill claims that his Econ and 40HP FICM tunes, and PCM tuning under 40HP are safe for non-studded trucks. Matt at Gearheads writes an SRL tune specifically for non-studded trucks. It's still a crap shoot, there are so many variables in how the heads are put on that any given truck could have issues, even with stock tuning. If you're running any type of pre-loaded tunes, or any kind of shift-on-the-fly tuning, you need to reconsider and switch over to custom tuning. Running canned tunes is asking for trouble.
Any canned tune claiming 100HP will almost certainly blow your heads, they usually screw with the start of injection table and make it really aggressive to get that extra power, and that jacks up cylinder pressures to the point where there's no way to keep the stock bolts from stretching.
This is specifically for the 7.3Ls, but it's still a good writeup from Bill about tuning HEUI diesels:
http://www.powerstroke.org/forum/99-...general-2.html
If you have a 7.3L:
Buy an FU chip or a Gryphon and tune away. The stock injectors probably can't move enough fuel soon enough to get the cylinder pressure to the point where you lose the heads.
http://www.gopowerhungry.com/_fu2_chip.shtml
http://www.gopowerhungry.com/_gryphon_cts_diesel.shtml










