The 365 is a 58. The 390 sounded great but it kept blowing the radiator hoses off. If it wasn’t for that you wouldn’t even known it was getting combustion gasses into the radiator.
Just by looking at the deck though even as pitted as it is I can’t tell where the leakage would be coming from since the areas around the cylinders seem ok. Which still makes be suspicious of the block itself…. I really need to ask around and find a solid machine shop. I’m learning that a bad one can cost you a lot of money and wasted time.
