The new engine had an alternator and HEI-style distributor on it, but once we got it installed we couldn’t get it to run. We narrowed it down to lack of spark but couldn’t figure out why. A call to Performance Distributors had us checking the distributor cap. For whatever reason, the engine had an even-fire cap on it (left). That led us to question if the distributor was correct for the application since the base of the distributor contacted our swapped-on intake manifold. Another call confirmed that we had an even-fire HEI. After double-checking the casting numbers on the block and head we ordered a new odd-fire Davis Unified Ignition HEI distributor from Performance Distributors.