Helping a friend with a 1966 Ford pickup. Unit has a 300 six cylinder. He would like to change over to EFI since he has continued to have trouble with carb system. Any suggestions?

Fix the carburetor or send to someone who can. If he wants it to start & drive like efi, add one of these. https://www.knfilters.com/eci

Unless he wants EFI for all of it's benefits, and wants to spend some serious coin, just get a carb rebuild kit and do it, or find a friend that can. Doesn't it have a single barrel carb?

Most of the EFI systems are designed for a 4150 carb flange, that will be the start of his conversion problems. Could modify his intake for port EFI (the right way to do things), but again, he is headed down an easy $1500+ path........... Can buy and fix a lot of carbs with that $$$$!!!!

Holley makes a 2bbl Sniper, under $1000. Easiest and cheapest way to go EFI.