Hi from Phoenix AZ! Picked up a non-running 1974 Plymouth Valiant Scamp

Nice Scamp, sir! It looks like you have the HEI upgrade, that's a good one. Also, a 75 is (I'm all but certain) going to be a lean burn engine. There are a herd of vacuum lines, gizmos, and wiring that go with that business. I trashed all that stuff on my truck since it's not required here, but you may want to investigate that deal. If out of whack it makes the engine run poorly.

If you need a new gas tank Spectra makes good ones that are affordable. If you swap it out make sure you keep the sender retaining ring off your factory tank and re-use it. The one that comes with a new tank is junk.

Keep the info and photos coming!