first off if you have leaked oil out of the headgasket and then taken it off and reused it you have a problem.

did you put the headgasket on right side up or upside down?? this happens alot!

also was the blocked checked for the deck being level? also the same for the head? if these 2 are not planed or decked flat they wont meet up no matter what kind of gasket you use......

last which holes and what way did you use the lsvtec dowel kit, in the exhaust side or intake side holes, it appears that they can go in 2 different ways by being flipped upside down