Wildchild467 has as high as a 95% leak down rate on his freshly rebuilt LDT/S hybrid engine with those pistons/rings, we just measured it last night with a new head gasket torqued into place and the rocker shafts left off. Piston tops look good, suspecting broken rings or ring lands. No valve leakage, NOS heads. We're not exactly sure what went astray, I'm blaming too much boost and/or unknown WMO fuel source for now. Could be anything in there, people at the dump don't care. His as-removed rings were also shattered, so that is two sets now. Suggesting he re-ring his previous pistons, back boost down to spec level, and empty/flush his fuel system completely and break it on in fresh, clean, diesel fuel only. If anybody else has done an LDT/S conversion (attempt), please get ahold of him and tell him your setup (boost level, fuel type, LDS conversion pieces added to LDT, and any data you may have such as compression or leak down). His truck ran strong at first, pulling away from my 925A2 off a light up to 55mph, then quickly lost power and turned into a steam engine via blow by out the draft tube and oil turning to sludge under the valve cover. He has a separate thread going near the top of this section, sorry I didn't copy the link to it before drafting this, but most of you will know him and his current situation. Thanks for the 66 pages of fun.