Mathematical modelling of Stirling engines has been a widely researched topic over the course of the last few decades. Amongst different approaches, many zero- dimensional models based on solving differential mass and energy balances have been proposed by different authors. As some of these models necessitate the use of heat transfer coefficients characterizing the convective processes in the heat exchangers, the method by which those are calculated demands close attention. The aim of this work is to validate different heat transfer models within the framework of a zero-dimensional model created by the authors. Experimental results are obtained from a rig based on a Genoastirling ML3000 engine. These results are compared with model results utilizing different heat transfer models, narrowing the selection to the heat transfer correlations of Anannd and Pinfold (1980), Toda (1994) and Kanzaka and Iwabuchi (1992). For the best performing models further, using a novel method based on the West number, refinement to the equations is proposed and evaluated showing an improved quality of model prediction in terms of indicated power.