I have a 29 fever with a 575 @ 750 hp, bought a 2 inch IMCO shorty and put it on my XR upper, tried 2 different props my original bravo 1 30 and a herring 5 blade lab finish 29 in both cases slip numbers are off the chart. Has anyone had similar issues like this? Should I put spacers on the the lower unit? What would be the best prop? Top speed so far was 83

Does that hull have a notch?

How far below the lowest point of the hull is your prop shaft?
Fountain's are known for high propshaft height.
You may need only a -1 shortie.

I recall seeing you can trial different spacers from BBlades to get it right. Other larger prop shops should offer the service too.

You should try a bravo or hydro 4 blade. A hering is a surface prop. You could also try hydro p5x if you think you want a 5 blade

Was really hoping to maybe find some one who has tried the different combo's and hear thier results

Not a 29 but I'm at 10% slip with a -2" Imco lower and a stock P5X on a non step 27.
Propshaft is about 2,5" below the bottom.

I had a 27 with close to the same drive height you have. Pretty sure you are deep. You have to find out how deep the propshaft is in comparison to the bottom . X dimention . Most stock ones are close to the same but you never know if it has been changed until you measure it.

My 27 had pretty high slip compared to a surface prop. I ran pretty good with a labbed 28 bravo and i could pull a skier behind it too ( it had a blower). The hydromotive 4 blade cavatated a little . Find out you x dimention, call BBlades . ( they will let you try props for 25 bucks for a week . Otherwise you are not going to get the best numbers off of what someone says on here imo. The p5x was pretty good on my 38 until i raised the x dimention.

I'm running a 29 with -1" IMCO shorty... Pushing about 640HP. My best is 82 running a 28 labbed Merc Maximus 5 blade. But, I have slung blades on 2 of them. It's getting expensive. My experience has been this: A labbed 30 Merc Bravo 4 blade likes weight. Best speed is with full tank and 5 people. The 5 blade likes it lighter. I have also tried the P5X... But, is was a 30. I think it was just a little to big. I liked the way it ran. It was not labbed. May try a 29 P5X next.