Does anyone have any suggestions on fuel rails(or where I should purchase them) for an MPFI setup on a Mopar 337 intake manifold?

I'm pretty sure the Edelbrock rails will fit. If you have a 337 intake on hand just measure from pad to pad and I'll tell you if the Edelbrock rails will fit. I have a set of Edelbrock rails here that I'm not using so I can double check the numbers for you.

Awesome thanks again Andy!! I should have the intake back from Larry Smith at Flow Tech on Monday, so I will measure from pad to pad and follow back up with you.

This might help you. If you decide you want to try the Edelbrock rails just shoot me a PM. I'm not using this set for anything. I thought I'd use them for a conversion but they didn't fit the intake I bought.

Excellent. Thanks Andy. I will have to measure when I get the 337 back Monday. Have you seen many 337 intakes with MPFI?

I don't think I've ever seen one with EFI but it should be an easy conversion since they are designed for it. Mopar Performance should've done a EFI 505 crate engine using the 337 intake. It could've been a killer setup.