I have 26 four blades on it It tops out at 80 mph
​​​​​​Still have the cable steering
It steers well but around 75 any small wave it gets dicey!
I think I could get a higher top end with different blades

I've always heard the 3 blade props work best on this set-up (with twin BBC's). More stern lift?? Per the orig owner, mine tops out at 83 MPH in fresh water. (A little faster in salt). I haven't got it above 80 since it was getting very squirrelly. Engs are supposed to be right at 500 hp.

It came with 25p 3 blades
I couldn't get it much over 70 until I switched the blades to spin in
I didn't have enough bow lift
I am guessing I took about 400 pounds off each motor
The swim plate form now sits 8 inches off the water

There is plenty of stern lift now

Way back when we souped up 29' Fountain 2x454 mags. Then we put 27 pitch 3 blades had prop shop add 300rpm each 77mph all day long!

Getting weight off the stern is a good thing with these boats. I still have cast iron Merlin intakes. They are seriously heavy. Swim deck on mine is abt 6" off the water.

Yes it makes a big difference!
I went with aluminum everything I could
Stainless exhaust and took the silent choice out. The V pipe alone was a lot of weight