21 sutphen..One of a couple small block boats Ritchie Jr built in 99. Stock mercruiser N/A 350 Magnum 250 HP alpha drive. Runs 62-65 with a 21 Mirage plus 3 blade. Looking for 70-75....Whipple? ...Land @ Sea setback? Rev limited at 4800 rpm...Any ideas?

...bg? demon?...used whipple sounds good Is alpha good for 300HP?

You won't need a lot of power to make that boat go 70mph. I have an older 20 that is powered by a stock 1991 7.4/Bravo and it runs 72 on the Merc speedo, spinning a cupped 25 Mirage. You can get there with good old fashioned cubic inches.

thanks Sutphil...It may be a bit early to replace the small block..is your boat a 91? where did you find it?

My hull is an 1988 which I bought new from a dealer in Muskoka, Ontario in 1993. The hull sat unfinished until the engine/drive combo was installed in 91 or 92.
Keep your small block, they are great and it's not that big a boat anyways. I was just illustrating what potential the boat has with stock power. There are half a dozen 20's around here and they are all small block boats that run about the same speed that you are getting. We have tons of Donzi's around and they are usually back there somewhere.

I had heard that the mold spent some time in Canada .. glad we're staying ahead of the donzi's. I just spent the afternoon scaring some guests in the 1-3 footers...love that hull. I'm jealous about that 72 mph