Got the motor all in,removed ac,power steering (replaced with manual)and air pump.Used the block off plate that came with the racing beat header.All new vacume lines,hoses and everything else.I am driving it around afraid to really get into her because it has a new a.c.t clutch and alum flywheel and i dont want to screw anything up before i get it broke in.Well my baby is letting me down,I get into it at around 3000 rpm she starts to die down then picks back up untill about 4500 to 5000 then same thing--want even think about going over 6000 rpm under a load.I am like what the hell,take off the fuel filter to check it out--OH MY GOD!--my tank is completely rusted.Now i have to get a new tank before i screw up the new injectors .The gas coming out of the filter looked like complet ****.This had to be going on for a while,i am just wondering after i put the new filter in i noticed not one bit of difference---same problem.Could it be something else?--The tank is going to be replaced but could i be missing something else with it running so bad.When its cold shes really bad.

good thing you checked the fuel filter

you can just drop the tank and have it cleaned

yeah kindof sounds like a fuel problem, I'd check your regulator, maybe installe a "t" in the fuel line and take measurement with a gauge. either your fuel pump isn't keeping up, bad grounds... something