If you have the Chrysler distributor, which is the MPG ignition ("miles per gallon"), then you almost certainly have the K-jet injection system.

"...with a large rubber boot on the bottom..."

Yep. K-jet. Sometimes K-jet is called "CIS" for "constant injection system" and sometimes called the "mechanical system."

Look, for example, at illustrations 12.10 (p. 4A-19) or 12.14 (p. 4A-20) for pictures of your engine.

K-jet injectors have only a black plastic hose connected. LH-jet injectors are attached to a "fuel rail," but also each injector has an electrical cable connected.

My Haynes manual covers K-jet and LH-jet together -- they're sort of mixed together in section 4A. I also have the green Volvo manuals, and these are the best.

I had (still have, but dead) an '82 245 that could squeak 31-32-33 mpg if driven carefully on the highway. Regular combined city-country driving was typically 26-28 mpg, and I drove with a not-so-light foot. Ordinary highway commuting was usually around 28-30 mpg.
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Don Foster (near Cape Cod, MA)