I picked up what the original owner is calling a ESR 370 kit. But what is wierd is. It is a 77mm bore. So it is a 330 pro x cylinder set up for 77 mil stroke. Would be a 369 on it's last bore. I did some searching online. Found one guy back in the day selling a 370 that was on 77mm bore. So just wondering if this is how they originally did what they considered a 370. Im good with what I got and what I got it for. Just trying to figure this out for my piece of mind.