I'm slowly gathering the parts to build a 318 LA motor with magnum heads.

I am also considering fuel injection given the availability of magnum parts in the junkyards at a cheap price.

Has anyone ever done this before, or are there any guides on what you need to do to modify a 5.2 magnum wiring harness to go into an old mopar?

what modifications need to be done to an LA block for the various sensors for the fuel injection system?

and just as a disclaimer, i was going to do the hybrid motor anyway with a carb, and i already have the majority of the parts, so no, i wouldn't consider just swapping in a magnum engine.

but the magnum shortblock has the ability to run a hydraulic roller cam in it very cheaply, reground cams can be had for $150 or less, or about what a new flat tappet cam costs nowadays.

if you plan on using the magnum computer, you need a crank trigger. on a mag, it's mounted to the rear of the engine in the bellhousing area. an LA doesn't have these provisions.

if it were me doing efi on the cheap, I'd use magnum parts (throttle body, fuel rail, distributor), the properly sized injectors (depending on needed flow rate, magnums, ones from a neon, or ones from a mustang), and I'd run the thing with either a GM TPI computer or a megasquirt.

There's nowhere to mount the crank position sensor on an early block. If I remember correctly it's been addressed in the past by making a bracket to mount to the head instead, but it isn't an off the shelf piece.