I had no idea that Hilborn make an EFI. For me they were known for making race engine mechanical injection that wasnīt streetable.
http://www.hilborninjection.com/index.asp
It looks great, and if it works good, is well worth the $.
My experience with an aftermarket injection system (TWM/Accel on my 427) is that the problems arise from the installation (consistent fuel supply), and the quality of the signal that the sensors get (MAP vacuum, design of the intake manifold).
Dyno and road testing are also essential in order for all driving situations to be assessed and mapped, it would seem.
Having bought my car used, I didnīt know how it was set up. Mine ran rich, caused bore wash and eventually piston slap after only 3000 miles.
After the motor rebuild, we will start the full process. I am still toally pro -EFI.
Donīt believe that because a motor starts and idles great, delivers great acceleration and top speed, and can run smooth and economical at cruise, that the motor is healthy. Mine did all that, but somewhere in the driving cycle it would run extreme rich, long enough to do damage.