So I have been studying for a while on swapping a 360 magnum into my 88 d100 with a 318 and a 904 transmission. All I need to know at this point is with my engine being neutral balanced does that mean I do not have to swap out the flex plate and torque converter or am I wrong? I know that the la 360 is externally balanced so it will not work for sure, but with me having the 318 and it being neutral balanced I don’t have to spent the extra money on a flex plate and torque converter?

 

360 Magnum is external balance as well. You need the harmonic balancer, and flexplate from a 96 or newer 360 magnum to install to your existing trans.

 

Just wrapping up a similar swap right now except I used a 727. You need a 96 and up engine. Get it with all the bells and whistles on it including the harmonic balancer on the front and the flexplate on the back. You'll know its a 96 and up because there will be 2 weights welded onto the flex plate. Your 904 should have a neutrally balanced TC (you'll see weights welded on it if it isnt neutrally balanced). Take the flex plate off the motor and sit it on the TC and youre going to notice that you will need to widen one of the holes a little bit in order to make it bolt up but nothing too crazy. Took me like a half hour and that was taking mm at a time and then checking how it lined up.

But basically thats the big one. Anything that was bolted up to a 318 should be neutrally balanced and anything over a 96 should be flexplate balanced (360 Magnum).

Depending on what your plans are other things will have to change. I can tell you that pace setter long tubes will not easily fit in the truck without cutting some of the frame + losing your column shift. (Im using it for off road so I was adding a floor shifter anyway).Hope you kept the distributor off the old engine because you'll need it unless you're going EFI. I chose to go serpentine belt for the accessory drive instead of belts.You might be able to change the pulley on your current power steering pump to make it into a serpentine but since I had a Magnum pump I found that it uses the same thread on the hoses so it goes right on. Alternator wiring is different and I havent tackled that yet. As well as the motor mounts are slightly different for some reason.