I have a 400 in my box van, and drive at a wide variety of altitudes with some pretty poor mileage. It has an Edelbrock 4BBL on it, and a performer 400 intake, so I'd like to throw a 4BBL TBI system on it. I have used the older Holley system and hate it, I was leaning towards the FiTech 400hp street system, but there are some mixed reviews.
I'd like to avoid MSII and similar DIY systems, I'd like to just have it work.

 

IMHO, you won't find much if any of either performance or MPG gain from switching to TBI

 

Well, given that I have run this thing from sea level to over 6000' and noted severe changes in it's operating characteristics doing so, I'd have to hope a lambda controlled EFI system would show some difference.
Last year I did the cleanup and final install on a Holley system on a 79 Chevy C70 cabover with a 427, while I absolutely hated the system, it did make the truck behave much better especially in varying altitudes and off-road.

 

Ok, I understand now...but in all honesty, I use to run on a daily basis from Lake Arrowhead (5,280 elevation) to San Bernardino for college.....did that for several years, I don't recall ever having to re-adjust the carb and my mileage stayed the same....but EFI would likely be more responsive to the AF requirements.

 

The best bang for your buck would be the fitech go efi. Just put one on my 400 and it's awesome. No more pulling over, swapping jets etc. Just change the value in the handheld and press send and it's done. At $795 it's a little more expensive than a carb. I will never buy a carburetor again. It fires on first crank, idles dead smooth, produces great power and self adjusts to the settings you program into the handheld. Oh did I mention it's a four wire hook up with a o2 sensor and temp sensor. Great product, just Google fitech tons of info on the web.

 

That's the one I've been looking at, the reviews are mixed, so I'm glad to hear you had a good experience.

 

never heard of a problem with the tbi unit, just the command center. Most people who have a problem with the FCC own chevys. When I plug my FCC into my vapor return line (like the instructions say) I have had no issues since. I have a 78 Bronco.