The purpose of this paper is to characterise the flow field through the inlet valves, and tumble to swirl conversion tube of a steady state flow rig using HWA. LDA and CFD techniques. Three cylinder head configurations were developed which were found to produce three levels of barrel swirl motion. The swirl precesses around the central core of the conversion tube at all degrees of swirl. Varying degrees of swirl produced differing axial velocity profiles, and flow reversal occurred in the central core of the conversion tube for the high swirling case. The results obtained for this study indicate that care must be exercised when deducing the barrel swirl ratio for real engines from steady flow rig analysis.