The distributor on a B230F can be mounted either behind the head (on the backside of the camshaft), or on the side of the engine just below the thermostat. The 240 series engines all had their distributors mounted on the side, but most of the 700 series distributors were on the heads (until some of the late model 940s that switched back to the side mount). Therefore, a distributor mounting position is not the most accurate method. (a B230F engine from a 240 or 940 that's been transplanted into a 740 is just fine)

Ideally, the engine part number would be the best method. It's on the paper sticker on the timing cover, and also stamped into the side of the block by the thermostat housing (and right next to the side mounted distributor location).

I'm not an expert on the "E" series fuel injection systems, but I would guess it would be Motronic rather than LH-Jetronic. The obvious sign of a Motronic system would be the Air Flow Meter, inplace of an Air Mass Meter. (flapper valve versus heated Platinum wire) However, you can swap fuel injection systems and engines quite easily, so that may not be a reliable method of identifying the engine.

I hope someone else has a better answer for you, otherwise you'll need to check the engine part number against an internet source or a Volvo dealership.

God bless,
Fitz Fitzgerald.
--
'87 Blue 240 Wagon, 255k miles.
'88 Black 780, PRV-6, 148k miles.