Electronic Fuel Injection

E.F.I. systems have sensors constantly testing the fuel ratio mixture so it adjusts to feed the proper fuel mixture in.

Stock E.F.I.

Many run their ported and polished cylinder heads with the stock fuel injection system and are quite happy.

This is definitely the way to get the best fuel economy.

High-performance

There are benefits to be had with a high-performance fuel injection system.

I've put together a few books found below, to help you.