lifted99GMC

iTrader: (4)

Im working on a car that is a 2000 z28. the engine was replaced in it before under factory warranty because it burnt oil badly. the new replacement engine has an ls6 intake on it now (no egr) and after 10000 miles or so the rod let loose and put holes in the sides of the block and it is not covered under factory warranty at 80,xxx miles(raw deal). He got a new block from texas speed, had it shipped and i am putting his factory rotating assembly in it with 1 new rod and 2 new pistons, new bearings and rings. The problem i am having now is that when i go to put on the heads, the head bolts are way too long, about 1.5 inches too long. so i compare the new block he has now to his old GM replacement block and the holes are recessed in the old block about 1.5 inches more than the new block. I called all around part strores and every year 98+ fbody and corvette has the same part number for the head bolts. The blocks are definately different though. could this be a ls2 block? i dont know the specs of everything for the ls1 style. I wrote down some casting numbers that was on the blocks

off of the old block (GM replacement for the 00) 12559378
there were a few numbers on the new block
on the back 12561168
and under the block on the sides
42270268 and k302059

also, on the ls2 engines, did they get the 6.0 L displacement through more stroke, bigger bore, or a combo of both? Reason i ask is because everything checked out fine (clearances) with the ls1 pistons in this new block with factory ls1 bore size.

thanks for any help

Chad

Blackbirdta2000

04 and up blocks have shorter bolts.