According to the conventional wisdom, the first stars formed in our Galaxy, including the massive ones responsible for most heavy element synthesis, must have had metal abundances much lower than solar. They may also have had somewhat lower helium abundances, corresponding to an enrichment ΔY/ΔZ = 2.7 ± 1.0 over the history of the Galaxy, a larger ratio than is readily accounted for by standard (Arnett-type) supernovae (Hacyan et al. 1977) or by mass shed from lower mass stars (Gingold 1977). But early nucleosynthesis must have occurred in stars with Pop II compositions. Several authors (Ezer and Cameron 1969; Cary 1974; Chiosi and Nasi 1974; Trimble et al. 1973) have modelled and evolved such stars, but none of the studies followed the stars far enough from the main sequence to be able to say anything very quantitative about their contribution to galactic chemical evolution. We address here the question of the effects of initial composition upon helium and heavy element production in massive stars.