Still pondering the answer to this question from studying various pictures the CIE Palvans were certainly taller than the standard 12 ton standard covered van which is 11'5", this excellent picture from J M Allen of a loose coupled goods which has a Palvan next to the loco illustrates the point very well the Palvan to my eye seems to be the same height as the 181 class which is 12'6" to the top of the exhaust manifold. Not very scientific but in the absence of an actual drawing might be the best we can get.