So not sure what the best plan is ..... any suggestions out there ??????

Search tells me GSL SE tank swap is the best tank , but I don't really want to cut into the back of the car to deal with large Spare tire well in the '79's.

Also don't really want to risk fuel pump flow issues on the new T2 motor using the stock '79 tank .

 

I've been modding 1st gen tanks by installing the 2nd gen sump cup and intank fuel pump. The SE sump cup is about 1/4 the size of the FC sump cup.

Your other option is using a low pressure fuel pump to feed a a surge tank and an external high pressure pump to pull fuel from the surge tank. The return line goes back to the surge tank, then on to the main tank.

 

any chance you have some pics or description of this skill you have with the FC sump??

sounds like a better idea than cutting up the rear