5.3l swap gas tank options

[henry3rd]

Hello guys,
I thinking of doing a swap to a 5.3l out of a late model silverado.
What options do I have for the fuel system? I have seen the ece underbed fuel cell. I like it, but it is kind of pricey. Does anybody know of a cheaper one? Can you modify a regular blazer tank for a in tank efi setup? I want to do something that is safe and cost effective at the same time. By the way here is a pic of the 68 I will be putting it in.

Thanks!!