Anyone know why GM changed the fuel rail when the LT1 went to sequential MAF in '94? I'm guessing the newer design somehow provides more even flow, but it was probably just cheeper.

 

The 92's and 93's were non return setups...

The 94+ setups had a return line. IIRC, it helps keep the pressure from backing up in the fuel rail, and helps keep the injectors from getting "overloaded" and spay more fuel than is necessary.

 

No, they are both return style systems. The same two supply and return lines are present on all year LT1s.

 

The only difference is the routing of the cross-over tube. Using a full series hookup like the 94's would seem to work best for sequential, because the injector pulses are sort of random, over the length of the two rails. I know the 93 rails have different cross-over configuration, but I don't know if they run the rails in parallel or in series.

A common modification for increasing capacity of the 94+ rails is to run them in parallel.