Hoping someone has better information than me.

Appears the tank itself is the same throughout all 2nd Gen 2 Dr Blazers (rockauto has same SKU so making assumption)

However, looking at buying an aftermarket sending unit with a 340lph pump, they only list 97-2002 for it, and say 2003/2004 won't work? Why would GM have changed the last 2 years of production; is it just a matter of the outlets facing a different direction on the later years, as I'm going to be running braided fuel lines I can deal with different outlet direction if that is in fact the only difference?

I've done some searching and can't find an answer for the above.

 

I'm not 100% certain, but I believe the difference is that GM changed the harness in 02, and most of the pump kits come with a replacement pig-tail that needs to be wired in to work.

I'm not sure if there are any changes to outlet direction in those years...

 

looking through some photos on rockatuo n ebay.. the 97-02 has a fat o ring seal between sending unit and tank, where the 03/04 is like a rubber sleeve almost... not sure how accurate the photos are, but does look like the later units have the outlets in a 180 degree fashion compared to the 97-02 but that looks like only differences... The 4 door ironically is the identical pump 97-04, go figure.

I'm gonna hotwire the fuel pump, and plan to run dual 340s, so outlets n wire size don't matter. Was going to buy a premade unit with a single 340 to start things off, and add a second down the line, but guess I will just tear into my factory bucket and look at putting in a 340 myself.

 

Good luck! I hope it works for you, and please share the outcomes with the community here so we can learn as well.