Praetorian

Merry Christmas all. Our household has slowed down after a big dinner and everyone is snoozing. I was hoping there were some folks still around that could help. I'm looking for some folks with more experience than I have to help me with some boat upgrade decisions. My '01 312 has twin 6.2s, standard steering, standard bennett trim tabs and runs about 64-65 on GPS. The boat is great. Looks great, built like a tank, runs and handles superbly and I understand she was built and rigged for a very specific market. It was designed to meet a price point, with acceptable, but not stellar, performance. Each year I bring her in for a thorough maintenance check-up and this year I know I'll need exhaust manifolds. I was thinking of upgrading the manifolds to Stainless Marine. With my set up, would I see an increase in speed? Also, is it worth labbing the props for a little extra speed? Reading posts on the board suggest there may or may not be any advantage to labbing the props on this particular boat.

The boat was originally sold by Robert Nelems and I got her in 03 from Legendary Marine in Destin.

Magicfloat

65 from a small block 312 means you are dialed in pretty good. You might pick up a small amount with Stainless Marine manifolds,but might not be worth the extra expense over stock.I wouldn't spend the money to lab the props. I think you are running quite well with the power you have.

Praetorian

Thanks! You confirmed what I was thinking. I could spend a good deal of money upgrading the boats performance. The 6.2 package seems limited for reliable performance upgrades. Could even Whipple the engines, but there seems to be a world of issues there also. There are a few things to do such as exhaust manifolds and labbing the props. But even if there were more you can do with this set up, I believe once you hit the magic "70 MPH" area, you need to consider external hydraulic steering and more heavy duty trim tabs. The costs add up. From what I've read it appears this boat's hull stability gets questionable at 80 mph and above. All in all, I'm thinking if I want to go faster, I would be better off investing the upgrade money into a larger boat, rigged for the higher speed.

t500hps

I had a 312 with 502's and all the upgrades....don't spend the money. If you want a faster boat, sell this one and BUY a faster boat. Yours is missing too many of the components needed and you'll never get any of that money back in re-sale. If you want to cruise at 55mph then just puch the sticks further until your running 55. Sure it will shorten the life of the motors some, but rebuild when that time comes is still cheaper than the mods needed to speed the boat up.

and btw: the hull actually stabilizes at about 80...at 74-75 it starts getting squirrly!!!!

Praetorian

I appreciate the advice. I absolutely love this boat, it runs great and sips gas. She handles rough water well but not as well as a larger hull and occasionally I would like to run her with some of the bigger guns out there.

I don't know if you have heard of this problem, but, I have noticed many times when I advance the throttle I get a noise from the passenger seat area. The noise usually gets louder as the throttles hit the rev limiters, and depending on the roughness of the seas, the noise will persist even when the engines are shut down and the boat is docked. I talked to a couple of friends of mine and they had similar problems and it cost them half of everything they owned to get rid of the noise. Interestingly enough, to a man, they said the cost was worth it.

Magicfloat

5PMSMWHR

Short term solution to that problem is like so many other things you fix on the boat.......duct tape, the wider the better.

Rippem

make sure you go all the way around the offending noise maker
simply putting a strip of duct tape across it may prove unreliable for an all-day fix.

t500hps

The easiest way to get rid of the noise is the use the duct tape on your OWN head...I guarrantee it will work!!!!