EFI return line, use emissions return?

Ah.. after reading your thread on EFI fuel supply, I noticed that you had a TBI/carb redundance thought...

Now this is a clever one I read about long time ago..

Use the intake manifold for a 4-bbl carb. fit it with injector bungs.. and use the carb as a throttle body! all you need to do is to attach a potentiometer to the butterfly-axle for throttle position sensor, and there's your throttle body!

Then you can just switch the fuel supply to the carb on and off at will! you will of course need one regulator for running carb and one for EFI respectively.

Now, my EFI has never failed, so personally, I consider such redundancy.. redundant, but it's still a neat approach if you want to do things on a budget.