The New 388 Skater Profesonal Marine Won There Class At The Shoot Out At Lotto They Ran 119 Alvin And Slug Ran The Boat Congradulations Guys

Is that with merc 525's?

Yes it was

I was watching a vid of a amsoil in port huron running and you can see the GPS get to about 120 in a race. Another video shows him hitting a record of 138. How did they pick up 18 mph. I'm assuming gear change and props?

Yes & conditions, also Amsoil is a 368 not a 388