Posting this for a friend. He has a 2001 38 ZX 500efi's his B1's spin out. Weve noticed many 38 ZX's spin in. Any advantages to spinning in? Right now the boat gets up on plane very well, is he leaving speed on the table spinning out?

Potentially speed is left on the table if the props are slipping at WOT. Check the slip %. If it is high at WOT I would switch the props on the drives and shift to reverse to actually go forward. If the numbers improve, switch the cables at the box and your good to go.
The inner rotation will leverage the transom more and potentially decrease some inefficiency if it exists.

Brett

what speeds is he seeing? From the factory they were spinning in, should be right around 76 to 78 ish give or take. I was told they ran fastest that way but never got around to trying it spinning out to see if it handeled any different.