The vacuum side can get funny and may require some experimentation. Vacuum is weird (dare I say it sucks?)
You need a vacuum line to the servo. Also one going to the brake pedal dump valve.
My donor was an 88 BII with a 2.9. Vacuum line went straight to the intake and had a check valve so I did that on mine. It surged bad (low vacuum) but since I was mashing together a lot of stuff that didn’t come together it threw me off. I hunted down a module from a carbed truck, I added a vacuum reservoir and as I installed that I discovered my hood hinge was pinching the vacuum hose on the top of the brake booster. Then it worked pretty good most of the time but it would still have surging fits. I did some more JY recon and noticed carbed vehicles usually didn’t have a check valve... so I deleted that. It had worked fine so far after that.
Going to Ohio it worked great aside from the trip out in Illonois. The bomb craters in the highway would make it surge. I don't know if it was the check valve sticking or if the PCV bounced and did something funny or what was going on exactly. And then after we got back it had two episodes without an impact.
No engine computer required. It does tap into the wiring of a EFI engine so the computer knows the cruise is on. My truck is a durasparked 5.0... so the aside from the aftermarket radio the most sophisticated electrical part on the truck is the cruise control module.
When I get the truck back together I want to bypass the reservoir and see how it works without it before I do a write up.
Factory install on a 2.9 Ranger: