There are a great many folks in aviation that think automotive engines cannot/will not work in aircraft. I believe these people are quite uninformed and, of course, wrong.
Some very good information about this topic is available at the following locations:
SDS - Automotive Engines in Aircraft
SDS - Automotive Engines in Aircraft, Part 2
Personally, I am not a big fan of using OEM ECU's (Electronic Control Units) for engine control (EFI). Early OBD (On Board Diagnostics) engines (1990 to about 1994) were relatively easy to convert to aircraft use. Current ECU's are extremely complicated with a huge number of inputs making them very difficult to convert. I feel that one of the aftermarket ECU's is a much safer and much better way to go. I recommend eith the Real World Solutions EC2/3 (like I am using) or the SDS system.