The "T" fitting I bought to add my Autometer sender sticks out too far and hits the block, so I can't get it to thread in. Would I be able to use these two 90's as shown to shim it out a little bit?
It's not a 1/8" NPT port, it's an inverted flare thread. You would need to fabricate a tube and cap it off. Otherwise, you can drill it out and tap a 1/4" NPT thread, then use a pipe plug.