2003 volvo c70 wont start after head gasket replacement

I recently replaced my head gasket on my volvo 2.4l turbo. i had he head re-surfaced. when installing everything back togather i put cams and timing right back exactly like they were. i never removed the vvt exhaust cam gear when i took it apart. i used the locking tool for my camshafts and put it back in time with all marks exactly like they were. i even rotated the engine 2 full turns to make sure nothing hit and that the timing still lined up. i tried to start he car and heres what it does. it cranks slow like its dragging, it occasonily backfires through the intake and the tachometer goes crazy while cranking, jumping up and down. i've re-timed it a zillion times seems like and get the same thing. anybody know what i might look for.? i'm at my wits end and clueless! any help would greatly be appreciated! thank you!