Upgraded Engine from 302 to 351 / now missing
 

When I purchased my 1993 F150 it had a 302 well it throw a rod out the side of the engine. A rebuilt 351 replaced it. I had a whole lot of problems over the last couple of years. The main thing right now is it misses terrible when accelerating. My mechanic had it for a couple of weeks with all the gadgets you can imagine and wasn't able to fix it.

Is there anything, computer, electrical or anything that should have been swapped out or changed? I know it's a broad questions but I'm just looking for any and all ideas.

Yes, all of that needed to be changed to match the engine. Engines aren't "upgrades" like a stronger bolt in a swing set - they're very carefully engineered systems, which include the wiring, exhaust, accessories, & more. You should have installed a direct-replacement engine. And 5.0L engines are NOT all identical - neither are all 5.8Ls. So without knowing EXACTLY what was done and EXACTLY what 5.8L went into the truck, no one can tell you what's wrong or how to fix it. The more pics, details, & PNs you post, the more likely we can help you figure out a plan.

Just as a first BLIND guess - what firing order did the mechanic use? Click this, read the caption, and let him read it, too:

https://www.supermotors.net/getfile/...ute94up_5l.jpg
(phone app link)