1973 28
 

Just purchased a 28 last night just wondering how much hp it would take to push it to 70mph? Its a prodject boat and has twin 406 smallblocks in it . Owner was in the process of converting over to Bravo drives when i purchased it. Keep it twins or convert it to a single?

keep the small blocks,if you change to a single bb you change the whole center of gravity and balance of the boat,i would leave it alone and enjoy it,good luck

a pair of 400hp 383s should get you to 70.

Thanks . I was leaning toward the smallblocks anyway. Gonna check the 400s out tonight to see if they run. Never heard of to many people installing 400s in boats . Not a huge fan of them . The previous owner stated they are 410hp a piece? We all know how that goes! LOL

Put a straight edge on the bottom last 10'. Make sure it's true.
A Lot of speed can be lost if the boat has a hook in it which it probably does.

28 ss
 

I have twin 383s a little over 500hp each it got up to and passed 70 easliy.

400hp. w/TRS's will get you to 70. The last time I re rigged mine I used aluminum heads and intakes w/ SM exhaust. It took a ton of weight out of the bilge and completely FUBARED the center of gravity.

mine were super reliable . 400 + hp got 78-80 on a gaffrig in my 28. A good balance job and a fluid damper or ati balancer is nessecary.

So as long as i dont try to re-invent the wheel i will reach my goal? Keep it basic nothing fancy 400hp each and i will have it? And keep the iron heads for weight?

I'd go aluminum. I only had Nordskog back in the day, but I had twin 406 pushing just over 400HP / TRS / Hydromotives and ran around an indicated 75. Good advice on checking the hook, as I had to correct that as well.

Post some pics!