Haven't put a big wheel on it yet. With a stock 21p which is what we race for the torque, it will run mid 80's. Gonna get with bblades for a 25 or 27p & see what she'll do in the spring. Might try squeeze 100 or so more hp's out of the engine by then as well.

Swung,
How many RPM's are you turning to get mid 80's with a 21" prop? According to Prop calculator, assuming 1.5 drive and 8% slip you need to turn 7000 RPM's to get 86 mph, 10%slip for 84 mph. Thats ALOT of RPMs for a big block! Wouldn't you be better off running a 24/25 pitch with less RPM? Just dont want to see your motor go "BANG".
Bob G. 606 Lock'd Up Bandit
http://www.go-fast.com/Prop_Slip_Calculator.htm

Hey Bob,

Your almost spot on. we only wound it up a cpl times with the race prob and it ran 6900 with the drive tucked. Could have got around 7100 or 7200 im thinkn if we raised it out of the water. To run 70 with that prop we are only spinning around 5700. so we arent hurting the engine at those rpm and we are in a good power band with alot of torque for off the turns and starts. Getting with bblades in the spring to find a nice top end prop. Want to get the boat running mid 90's in bar hopping trim, lol.... However, the boat handles awesome with the 21p so most likley we'll keep racing the 21 or possibly a 23 but not any bigger than that.

is that the old interstate battery boat?

Yes it is.

did you get the new prop yet? if so what was your top end?