I have had the Holley Pro-jection "2 barrel" TBI on the 383 in my Newport for many years. It uses throttle position - rpm. Originally, I had the older analog box (long). It ran OK for years w/ the O2 feedback, which is a clumsy "kludge-on" box with wires that tap into the harness. It looks like the earliest box w/ MSD label is best since it uses "weather-pack" connectors. My later box has a Molex type connector and the wires have pulled out of their crimped pins.
About 1 yr ago, I switched to the little "digital" box (cheap on ebay), which I bought for my Dart. The O2 sensor plugs in directly, but no light to tell you when rich and it doesn't seem to control O/F. It seems to run much worse. I have to constantly adjust the knobs between morning and evening as ambient temperature changes. It went rich and blew up my muffler twice. The little box gets hotter, and either box will run really bad if it sits in the sun.
I think the current design has an inlet air temp sensor, which should help. I also heard that the later TBI's are much better. My two are the older ones with the round connectors above the injectors. I wouldn't pay the >$1000 for a new system.
There are after-market TBI systems based on GM parts and controller which are probably better, for about the same price. Search the "Air-Fuel" forum for more info.
