Hei conversion Intermittent start?

From the pic above, it appears the battery is grounded directly to the block, which is OK for the Altenator. However, I did not see a ground strap to the frame, but it may be at the rear of the engine. Depending on your motor mounts, you may not be getting a very good ground to the frame, and this could be a contributing factor. It's not the altenator per se, but rather the battery grounding to the frame.