So I blew the 5.2 up at a mud bog last weekend. It was having that stutter problem most of the day but she still ripped up the mud. What I want to know is, will I need a 5.9 PCM if I put the 5.9 into the truck? Stock it came with the 5.2.

will I need to change anything else with the new motor?
thank you

 

Either a 5.9 PCM or a 5.9 flash for the 5.2 PCM. If you don't it will just run lean in open loop. So not entirely necessary

 

Keep in mind, the 318 and 360 (I'm old and not metric) are balanced differently. One is internally balanced and the other externally.

 

Good point, and also, HOW the 360 is balanced changed over the years as well.

What year is your truck?

 

98, what would I need todo different for the 360 then? I see the PCM isn’t needed but I’ll probably swap that anyway because it might’ve been a problem before with the 318

 

On that year, the balance weights for the 360 were on the flexplate. Just use the correct flexplate, and you are all set.

Also, being you use your truck in the mud...... you REALLY want the correct programming for the larger motor. (as you probably spend a fair bit of time in open loop, and running lean while under load is just bad. Tends to blow holes in pistons. ) So, PCM flashed to the correct VIN, and the correct programming for the engine/trans.

 

I know alllll too well about blowing rods and holes in oil pans lol. I plan on doing this build right so I’ll definitely be doing that.

do I NEED to reflash this PCM or can I just swap in a pcm off of a 5.9 truck?

 

Either way will work, reflash might actually be cheaper.....

 

Personally I'd reflash as uppit know your computer works. A junkyard one might not

 

If I got it reflashed for the new motor, would it “marry” to this truck? As in, would this top code go away?