Head gasket or cracked block...?

I recently put a new dss 306 short block in my 90 lx. WIth alot of other things as metioned in my sig. also some stuff missing probably..anyway, after about 500 miles there was a knocking, found out to be that the thrust bearing on the crankshaft had too much play and was alittle mangled. Sent the block to dss, said they wouldnt cover it for warrenty cause i installed it to the torque converter "wrong". my converter and tranny are perfect, they were checked out afterwards..if i installed it wrong, it would of f-ed my tranny up. so i got screwed by dss there. Now..i got everythign back and assembled by a shop this time..didnt feel like doing it twice..paid a **** load of money..and now..just got it back last week..and i over heat like a mother. Got it blocked tested, to find that there is tons of compression leaking into the coolant system. Im going to run some tests including a compression test first to see what cyl it is. BUT, what do you guys think it is..from experiance. I have thumper heads ported and polished. ...The shop said it could be a cracked block, head, or gaskets not torqued/put on wrong. heres the deal tho, Oil is crystal clean, antifreeze is clean. No white smoke out the exhaust. No fluid leaking into cylinder. I really hope my gaskets are just put on backwards or blown..but then again..why would they blow in the first place..
what happens when u run the car is sometimes it will act like the thermo doesnt even open..fly right past 180 and bury the need at 260 on the gauge. then come back down. or stay up there. and no i didnt let it run when it got that hot lol...if you open the rad. cap and let it run..tons of air bubbles..and fluid within 5 mins come puking up out of the rad.

bump

nah theres compression getting into the coolant dude..i already told ya...i have a block test done.
also important question ARP HEAD BOLTS. Can they be reused!????? cause they were.

i dont know im not sure about the sweet smell..god i hope its not the block..thats alot of work to do again...ugh..i just wanna get rid of this thing now. Question. Im tryign to do a test of blowing compressed air into the cylinders to see which cyl bubbles through the rad... How the hell do you get both valves closed? WE thought we had them on number when it was on top dead center..but when we shot the air in it moved the motor and the air always comes out through the intake!? how the hell do u do this test and know that the valves are closed???

ok well did a test of blowing air into each cylinder.. number 6 was pushing air into the rad. the fluid rose and flowed into the overflow tube within 30 secs. Ok so today i started ripping **** apart. Got everythign off except the heads and headers. Now..one thing i did find was that if anyone bought a GT-40 intake kit. There is a smaller bolt supplied with the upper intake. That is suppose to go into the bolt hole on the left side of the front of the intake... It says on the paper that it is important. WHen i got it back from the shop, they had that bolt in the back! does that really matter or might they have ruined something??
Now heres the big question...WHen i removed the lower intake...when i looked at the bottom of it..WHen you look inside the runners ..NUMBER 6 had alot of what looked like oil buildup. It was near black. And thats the only runner that was that bad. u can def. tell. The buildup was up mostly buy the injector not down deep in the runner. Does that give me a sign of something???

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come on help me

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yea it actaully was the gasket...it was deteriorated/blown around the top of number 6 piston and was pushing it into the waterjacket....thats why i had bubles in my coolant and was overheating like a bitch...
it was a felpro but it was an econonmy i think..they looked like ****...i was always told to use felpro 1011-2's so thats what im gonna use i suppose