hosepower/ cost breakdown

Doug Durako · Nov 18, 2002

Here's one for a cold Monday morning from central Illinois. I've saved for a long time to get a fast boat. We won't go into the reasons why I need speed---lets just say I'm in my 40s and I have convinced my wife there are lots of other things I could focus on that would be worse than a faster boat. I bought nice little 19-footer last summer and it runs about 60 on the speedo at 4800 rpm (1999 carburated Chevy 350/250hp, Alpha drive, standard exhaust setup through the drive unit). Anyway, I've boated for more than 20 years and I know about propping options to get the most from the motor/drive combination. What I would like are the opinions of people on this post regarding the cost---starting at the cheapest and moving to most expensive---of getting 50 or more additional horsepower out of my motor? I probably won't do the work myself, but I might be able to get the boat into a heated shop of a friend so I could assist and learn. I've learned a lot from this forum and I would appreciate the input---Thanks!

geriksen · Nov 18, 2002

Re: hosepower/ cost breakdown

Speed costs money. How fast do you want to go? That sounds like a nice simple rig. Are you sure you want to start on this? What prop are you running? Have you tried a Mercurey Laser II? They are usually worth a couple miles per hour. You could put a whipple charger on it. They seem to make a decent kit. the only problem with that is the kits that go on a stock engine don't make much boost and dont do that much. To do it right you will need to put blower pistons in it, upgrade the fuel system, pump lines etc. and re-jet the carb. I have a 16 Donzi with a blower on a 4.3 that runs great but it was done right (read- expensive)

Doug Durako · Nov 18, 2002

Re: hosepower/ cost breakdown

Geriksen----I'm comforable with the current performance, but would really like to get closer to 68-70 mph---I think the Baja hull design I am running could get me there with more power and the right prop. I'm experimenting with props, but Rich Boger over on the prop forum says I should stay with the Mercury Vengence at 21 pitch. If I go up a bit in diameter I might be able to hit 63 mph, but I don't want to lose too much in RPMs. That's why I am looking at the hp side of the equation. I'd like to do a couple of things each winter for the next few winters and wanted to get ideas on what to do first, etc. This boat is going to be with me a long time, and I want to take my time and do it right.

CTD · Nov 18, 2002

Re: hosepower/ cost breakdown

order a catalog from Summit racing http://www.summitracing.com/ or Jegshttp://www.jegs.com/ You can send a lot of time looking at all the goodies they have for the small block chevy. It wouldn't hurt to try to find out more from the manufactuer as to what the specs on your current engine are. I would think you would want to keep idle quality so your limited in cam selections somewhat.

geriksen · Nov 18, 2002

Re: hosepower/ cost breakdown

I think the Vengance is similat to the Laser II. The blower will get you there. You have along winter up there. I would do it all the way with the low compression pistons so you can crank op the boost and really make it go. I am running 9pounds + of boost on a 4.3 and have run the daylights out of the boat for 6 years. Low compression and a big fuel pump and it will live.

coupedeville · Nov 18, 2002

Re: hosepower/ cost breakdown

Exactly how much are you interested in spending on this middle age crisis? Do you know if you have a Vortec 5.7 engine or not? The intake manifold bolts on a Vortec point almost vertically, an older style are on much more of an angle. For under $1000: New intake/carb, maybe heads. If you don't have a Vortec, then installing a set of Vortec heads and a matching manifold is the best bang for the buck around. Should be good for 50 extra ponies. Got more money to burn? A stroker motor, or a crate motor, or a supercharger.

geriksen · Nov 18, 2002

Re: hosepower/ cost breakdown

Beware! You do not want to buy fuel system or ignition system parts for your boat from a hot rod supplier. Automotive parts do not belong on a boat. Yes, I know they are cheaper, they will bolt on and they will work. Carbs have different venting systems, fuel pumps have and extra diaphram and an external dump. Distributors have screened or angles vents etc. You need a solid fuel line from the pump to the carb. Marine only, or you can unintentionally build yourself a bomb.

coupedeville · Nov 18, 2002

Re: hosepower/ cost breakdown

Well naturally I mean to use a marine carb. Both Holley & Edelbrock make authentic, genuine, won't blow up in your face marine units. http://vsholley.vwh.net/HiOctn/ProdLine/Marine/Carb/1MCL2.html http://edelbrock.com/automotive/marine.html

geriksen · Nov 18, 2002

Re: hosepower/ cost breakdown

O.K. don't forget the solid fuel line and the flame arrestor.

495v · Nov 18, 2002

Re: hosepower/ cost breakdown

ddboater, I also have a 5.7 Magnum Mercruiser and was toying with the same idea. Problem is it gets very expensive, almost better off selling and buying a faster boat.(Allison bassboats can top out around 100mph right off the showroom floor) One thing I did come across that alot of people sware by, A stern jack by Land & sea. Gives you an increased x dimension. The websites says that it can add anywhere from 3-10 mph on your top end, and also gives you better gas consumption. I beleive the cost on them was around 2k. Gil headers with thru-hull exhaust was also recommended for a few extra ponies.

geriksen · Nov 18, 2002

Re: hosepower/ cost breakdown

That would be worth a try. The thru transom exhaust will make is seem faster too. If you put the drive extention on, make sure that you keep the gimbal ring bolts tight. These are two bolts at the top of the steering ring outside the boat. You don't want that to wear out (about $1,000.00 to fix) This way you good leave that good running engine alone.

coupedeville · Nov 19, 2002

Re: hosepower/ cost breakdown

Howzabout a blower? Procharger has nice marine units. www.procharger.com

Doug Durako · Nov 19, 2002

Re: hosepower/ cost breakdown

Thanks for all the suggestions so far! I need to look at all this motor stuff (only marine stuff, to be sure). I have investigated the stern jack and read all the testimonials from Land N Sea, but I just need to really DRIVE something like that before laying out $2500. I can probably only get about $1000 past the CEO at home this winter. I used to spend that on cigars so I am saving her $$ in the long run and I smell a lot better too. I'm sure I will have more specific questions as I investigate further.

John Carpenter · Nov 19, 2002

Re: hosepower/ cost breakdown

One of the easiest and cheapest ways to pump up the 350 is to have it bored .030 over and install a crank out of a 400...this creates what is known as a 383 Stroker and will up the hp to about 325. Any of your hot rod friends should know all about it. If not, do a Google search on 383 Stroker. Good luck with your project.

coupedeville · Nov 20, 2002

Re: hosepower/ cost breakdown

The stroker is a nice idea, but you'll be hard pressed to do it for a thousand bucks. Intake- $200 Carb- $400 Vortec heads $450 a pair If you have a modest amount of mechanical skill, you can do it all in a day.

mkast · Nov 21, 2002

Re: hosepower/ cost breakdown

Please keep in mind, this is a boat. You will more than likely be better off taking your thousand bucks, using it as a down payment and trading your boat in on a boat you'll like a whole lot more. If you try to get some more horsepower out of the boat you have now, you'll have spent alot more than what you are thinking about spending now! What will your boat be worth after the mods? Are you going to get that money back on resale or insurance claim? Added hp to your "how old drive" New boat will give you a warranty, get that from the people doing the mods, fat chance! I pulled a 260 hp out of a 23 footer, installed a 330 hp. I picked up eight mph! It cost more than one thousand.

beckerdg · Nov 21, 2002

Re: hosepower/ cost breakdown

One other issue on the extra horsepower. Your alpha drive is good to about 300hp. If you take it to 325 like the stroker suggestion, you are where mercruiser was when they were selling the 454s with alphas. I don't think they did that very long. I am no real expert, but if you find a cheap way to get over 300hp, you may find yourself with an expensive outdrive repair later when it self destructs.

911d · Nov 21, 2002

Re: hosepower/ cost breakdown

Jollyroger, you beat me to it!! Alpha I is 300 max, and that is with a 1.32:1 gear set, and the different bearing set needed to run those gears! So, if you make over 260 hp, plan to upgrade to the 1.32:1 set (~525.00 + 150.00 brgs, seals).

Walt T · Nov 21, 2002

Re: hosepower/ cost breakdown

50 HP will come at a price. A blower is about the only thing that will get that kind of HP. Then you will need to worry about the bottom end of the engine and if it will stand up to it.

geriksen · Nov 22, 2002

Re: hosepower/ cost breakdown

These guys are right. You are in the area of diminishing returns. Lots of money and headache for not much better a boat. Carbs and intakes won't do it. The blower will do it but you cant even start that project for $1,000.00. You can take the price of the blower kit, add labor (double that), re-gear the drive, upgrade the fuel system, re-prop the boat, clearance the engine lid, etc. etc..... Then after all that you go to the lake, hit the throttle and hope it all holds together. Sound like fun?

hosepower/ cost breakdown

Chief Petty Officer

Petty Officer 2nd Class

Chief Petty Officer

Petty Officer 1st Class

Petty Officer 2nd Class

Petty Officer 2nd Class

Petty Officer 2nd Class

Petty Officer 2nd Class

Petty Officer 2nd Class

Chief Petty Officer

Petty Officer 2nd Class

Petty Officer 2nd Class

Chief Petty Officer

Petty Officer 1st Class

Petty Officer 2nd Class

Lieutenant Commander

Petty Officer 2nd Class

Recruit

Lieutenant

Petty Officer 2nd Class