Just Curious, i'm getting closer to pulling the trigger on a HP upgrade (cams and heads). Just wanted to get an educated guess on what increase in speed I will get by adding conservatively speaking 120HP total would I net. Of course this would include new prop's...again.

~10 mph would be my guess

Andy- I added just over 300 horsepower to the Fountain when I did it and picked up about 15 mph...just sayin'....

I've read 15-20hp =1mph

Yeah, but that was a Fountain not an AT. I hear you loud and clear. Not sure I want to open up 580 hour small blocks for 10 mph and cool sound factor. Should probably start putting $$$ away for it's replacement instead.

Cool! This will be VERY interesting to some of us.....or-r-r... maybe just me.

Good luck Andy

Save your $ for a pair of Ls small blocks

I'm thinking XM270HR Cams, Heads, Total Seal Rings, Bearing refresh, and MEFI Burn might be a couple dollars less then say.......2 new engines. Unless you have a couple to spare?

120 hp 5-6 mph tops

Replacement? Of the boat or the engines?