Here is what I noticed and it might help you out. If you are using Cometic Multi-Layer head gaskets ( I think these are junk) they tend to leak a lot no matter what people do. But, if you real want to minimize the leakage, you have to install them by the book per say. The only way (Im sure others will disagree cause maybe they had luck other wise) they will seal correctly the first time is to make sure the block is flat (most likely it will have to go to a machine shop and get decked) and the heads have to be completely flat also (get these done at the machine shop too!) Then I would use arp head studs and u must use arp moly lude (do not use motor oil on the threads to tq down the head nuts) If you do all this, most likely they will seal correctly. If you do no do all this, then use the other style (stock type) head gaskets. You may also have to re-torque the heads after you drive the car or run it to operating temp. If your mech used Cometic (or simalure style gaskets) and he didnt do all this stuff, its just a matter of time before they leak!