The availability of high time resolution spacecraft data has made possible in situ and detailed study of plasma processes in the interplanetary medium. One important process that has received a lot of attention is the energization of charged particles due to interaction with traveling interplanetary shock waves. The specific goal of this study is to make use of observed magnetic fields, plasma density and velocity, and initial particle trajectories calculated from real spacecraft orientations in a time-reversed computer simulation which follows particles through a single complete interaction with a shock in order to predict the angular distribution of energetic protons (0.29--0.5 MeV). This study is fully three-dimensional and unique in that real conditions for specific shocks outside the Earth's magnetosphere are simulated, and the results are compared to observations for each particular shock. Energy gains and losses calculated in the simulation are used to predict the amount of enhancement in each sector, assuming an isotropic ambient medium and a relationship between energy and particle number that is based on a power law. This study is a test of single encounter shock drift acceleration for two real shocks: 1974 day 312 (&thgr;Bn=68¿) and 1979 day 95 (&thgr;Bn=54¿). The first is clearly a quasi-perpendicular shock while the second has the long rise time associated with an energetic storm particle event with a shock spike just at the time of shock passage features, i.e., the observed angular distributions in the lowest-energy proton channel of the IMP 8 spacecraft for sectors which interacted with the shock. The 1974 day 312 shock is an example of the model correctly predicting the observations, and the shock spike of the 1979 day 95 shock offers a good base for comparison with the day 312 shock. ¿ American Geophysical Union 1988