We have purchased our 1988 Regal in March of 2023. We did not use it that year, we worked on the "house" reno projects and did the annual RV road trip in out 1988 Bluebird Wanderlodge that we sold in the fall.
In the spring of 2024 we finished most of the reno and in early spring I left it with the local shop that promised me to install TBI on it. As advised, I purchased Holley Sniper TBI unit and high pressure in-tank fuel pump - was not cheap, abot $2,000 total. I wanted to get it done for reliability, performance, and MPG reasons. Unfortunately the shop couldn't get to it due to, you know, excuses that are not worthy mentioning. That summer, with no fuel system upgrades, we took it for about 5000 miles trip to Canadian Rockies and Montana. We averaged 5 MPG towing CJ7 Jeep, with questionable reliability including lack of power, occasional back firing, fuel and exhaust smell, etc.
Upon returning home, the original shop had more excuses not to do TBI install. I couldn't find anybody willing to do so, so I, aging truck driver with limited automotive knowledge, decided to do it myself with the help of AI and Youtube. That's how it started on November 12, about month ago. In the next posts I will outline steps I took.

First, I removed fuel tank in order to install in-tank fuel pump. I borrowed raiser ramps from a friend of mine and used my trusty transmission jack to get it done.

Next, cleaned and painted the tank. Install new fuel pump for the fuel-out line, and reinstall modified old unit: removed the old pump and its power cable but kept the fuel level sender. Used old unit to connect the fuel return and tank evap lines. After that, I run brand new 6AN Nylon Braided Fuel Lines - fuel-out and return, and new fuel pump power cable all the way up to the engine bay.
Before reinstalling the tank I created an access hatch under the bed so now I am able to check/fix fuel my tank hardware from the top without removing the tank.

Next, I sorted out my exhaust - the gaskets between manifold and down pipes were gone! I replaced them and I removed a heat riser valve that was located on the driver side exhaust downpipe. I installed kit-included Oxygen sensor using smart adapter provided by Holley on the passenger side downpipe - really easy with no welding involved. I installed provided coolant temp sensor in the coolant hose leading to the water boiler using this hose adapter: Murray Climate Control Heater Fitting - 84540. This hose is easily accessible and provides constant flow of coolant - perfect location for CTS.
Next, I disconnected the battery and I routed dedicated 12V power cables directly from the battery terminals. The other needed cables; ACC and run on, and Tach I tapped directly from my HEI distributor. I installed control touch-screen unit on the dashboard and routed its cable to the engine bay.
I took my time to nicely clean engine bay and to sort out the vacuum system. About that time I replaced all spark plugs and plug wires.
At this point I was ready to complete the install.
I removed old carb, fuel line leading to it, and the old mechanical fuel pump. I installed fuel pump block-off plate.
Next, I bolted the TBI unit. I connected throttle and cruise linkages using provided bracket - perfect fit! I connected brand new fuel-in line trough the proper filter, fuel pressure gauge, and into the TBI fuel-in port. I connected my return line trough the Holley fuel pressure regulator to the TBI return port.
Next, I made required electrical harness wires connections to wires I prepared earlier: fuel pump, 12V+ and 12V-, ACC ON, and Tach. I plugged the harness and sensors to the TBI.
After re-checking all the fuel and electrical connections, I reconnected the battery.
The big moment arrived! I turned the key to the ON position and I followed the simple initial setup using touch screen control unit. After that, I did initial run and she purred like a Kitten!

Final Notes:
Test drive showed fantastic performance. No more power lag, no more backfires, instant throttle response, smooth cruise operation, much quitter, no smell of gas or exhaust. I will report on MPG in spring since I already parked it for the season. In spring, I also will be installing Gear Vendors overdrive unit so MPG results should be interesting.
It took me about five weekends to complete this job. I am not a mechanic, I am aging truck driver. I did a lot of figuring out using AI and Youtube. That figuring out things took me the most amount of time. For example, it took me two full days to find solution for Coolant Temp Sensor location. After poking around the engine and around the web I found a $30 solution that installs in less than 15 min and works perfectly.
I truly believe that knowing what I know now, I would be able to install that system in one weekend. Yes, that's correct: one weekend. Holly got great tech support as well so I would encourage any of you considering this project to get it done.
In this writing I omitted a lot of small details, part numbers, routing options, couple mistakes I made. Feel free to contact me with any questions you guys might have.
Good luck and yes, you will hurt and you will blead. If you ever fixed anything on an old RV, you do understand!
Peter

Nice! The TBI I installed a while back was a modified GM 2 barrel system that took a bit to get it dialed in. Once done it was a major improvement, starts better, runs better hot or cold, more power, better mileage. Like you, once I had done it, it was not a bad job to install.

That Holley system looks really nice. No welding on O2 sensor is nice. Sounds like you did a great job. Thanks for posting!

Fantastic post, Thank you Peter!

First class installation, and material usage!

Be curious as to the milage improvement!

Nice work, nice results, nice explanation!

Matt