Is a radiator for a 1994 S350 diesel the same as a 1994 S320 gas. Im wondering if I can install one from a gas engine model or are diesel radiators inherently bigger as is most everything else on a diesel. Thanks

Take a look at the BEHR / HELLA web site. they have a excellent rad/heater core/oil cooler/ rad fan catalog with pretty good dimensional drawings. just going by the part # isn't always going to show a interchange as hose location might be different.

Sometimes issues like this can be overcome with a bit of adaptation.

It will fit but the neck in the bottom is in different place for the S320

The v8 one is probably more similar to diesel rads than the gasser i6, the output neck should be on the bottom right at least (as opposed to the i6 having both on the left).