well, thought i would open the head, o-ring it, add twins and a couple other little goodies before Tulare. Took the head over too a buddy of mine to hog it out and after magging the head, i found out it was full of cracks, COL... (cry out loud) Took a look at my B-1 and guess what, COLx2 (cry out loud again, ... . but louder). If u see my sig u will see that i am only running dd2's, so be careful everybody. EGT's kill motors, ..... and $1,700 turbos that don't cool anything down, oops. Any ways, this is mainly to let people know that although the B-1 maybe rock hard, it's exhaust housing is still made of cast iron and still cracks. This is the big B-1 too,. (16 cm). i hit 1500 a couple times, but never for more than ten sec. Hope opening the new head and installing the twins reduces egt's enough to keep the cracks away. Not flaming at all, just pre warning those of us who think are motors are undrestructable. The price we pay to have fun! Yep, and i'm gonna do it again, just for a couple more HP! More power to the Cummins owner! ... . later, Reb