Please help. This is my first engine build and just finished breaking in the cam. Its a 1969 350 two bolt main with stock cast iron heads. I just noticed a hissing and very small drip coming out of the driver side front bolt hole. But looks like an accessory hole. Im not sure what its for. Can i just put a bolt in it and be good or could that be a cracked head? I circled the hole in blue in the pics.