So I was at Sun N Fun planning my RV's future. Was talking to some engine guys about 8.5 or a 9 to 1 compression. Not really caring about adding more HP or burning mo gas. Just want a good solid engine. I was just planning to go with an 8.5, but I was told that the IO 540 actually prefers a 9-1 ratio. I know it adds some HP, but according to the engine guy, he said its better all around for the 540 series engine. Is there a difference beyond some more ponies.