Holley Avenger EFI TBI setup

[dmsz28]

Hey guys,
I've been lurking on here for a while, reading and enjoying everyones trucks. But I've come to a point in my project where I need a little help. I have a holley avenger efi setup going on a 383 in an '81 GMC Step Side. My questions is, instead of spending a lot of money on an aftermarket fuel pump and lines, can I use the sending unit out of an '87 model that has the fuel pump on it in my '81 tank? The holley tbi uses the factory GM fuel pressure, about 15psi i think. So I'm curious if the 87 sending unit will fit in the 81 tank. Any input would be great. Thanks, David