Why do you need a sumped tank? I ask only because I used to have a sumped tank/external fuel pump in my 78 w/LS1. It did work well but was noisy. I now have a 4th gen fuel bucket fit into a new 2nd gen tank. Quiet, reliable, GM OEM part.
My sump was done by the previous owners...I believe the sump came from JEGS.
Leon
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Leon Reed
1978 Trans Am
LS1/4L60E