Well i finally got my Marks exhaust in the mail and have started the task of installing it, i have gotten to the point where i need to start tightening all the bolts to the engine and am having a small problem, it seems that the bolts for the front header is to long and i can't get it tight enough, i can't see any threads anymore and its gotten really tight but the header is still loose, am i missing something here? the back ones seem fine, its just these front ones. Also can anyone tell me what the tab on the crossover is for? also the two nuts that was included with the system?