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I NEED more power

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Airboats on susquehanna river bank eary 1960s millersburg pa
Beware
Putting on the wire.
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Levee Bird
The Ridge
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webfoot1

Active member
I need it guys....POWER that is!

I'm running a 16x7 Marks hull DD 350 chevy.....(still runs hot, need help there too.....) She runs good empty, but come duck season it may be a different story with a load. I've managed to get myself stuck a few times (fun gettin' there, not so much gettin' out!!!) I want to have the power to run semi dry better and the power to get back up on ice when I break through......

It's swinging a 70 inch wood paddle prop. I want a reduction unit something wicked, but all you jerks keep telling me to save my money and work up slowly!!! :lol:

My real question is, I'm in freakin' Illinois and gettin' some real help is pretty hard. What am I looking at cost wise for a reduction kit and new prop? How much will it help to go to a 72 inch composite? How often do props come up for sale used? AND who do you guys recomend taking the rig to to have the work done?

You guys have been awesome to my new airboat owning arse, thanks! :D
 
yup....I had the same thought come to mind. APOLOGIZE and you MIGHT get some help. Most midwesterners I know don't exhibit that type of attitude.
 
I didn't take any offense to his statement, and I think it was said out of fun.

Webfoot, if power is what you are looking for, a 383 stroker kit will be a wisely spent $1,000.

What cylinder heads do you have? Vortecs or a good aluminum head will net you good power and cost around another 1000.

Cool thing about these mods is, you can do them for about a grand a pop, and they don't have to be done at the same time like a gear box and prop upgrade. Also, when you do get a gear box, your power mods will still be very useable.

How big is your radiator, and what kind of setup do you have? I have a big 2 row aluminum radiator (200 bucks) on the back legs of the engine stand, and an expansion tank up on the cage ($80) with two hoses running up from the manifold. If your radiator still has a cap, make sure it has a higher pressure rating than the one on your expansion tank. I'm running a 16 pound on the tank and an 18 pound on the radiator.

I also run a 160 degree Superstat thermostat from NAPA.

This setup runs between 150 and 160.
 
I can assure you most stock 350's with a 2.68 gearbox will run as good if not better then a 383 with a 2to1 gearbox.
 
You're right, but the question he asked was what can he do for more power without going to a gear box and a different prop, and the re-rig required.

After he has gone to a 383, the 2.68 box will still work excellent later.
 
Webfoot, I saw your comment about jerks as a joke, I'm quiet sure you ment it that way! I'd help you if I could, but I'm still asking for help myself. You came to the right place for info. These folks know their airboats, good luck.
 
Webfoot, this is only one man's opinion .....

Sounds like you've got a nice big, roomy boat. The only problem is that it's also got a lot of wetted surface and it takes some serious push to move that.

Depending on your expectations of course, I'd reccomend that you consider lookin for a reduction drive for your engine. You're already talking about a bigger prop .... get a redrive and then you'll be able to swing an even bigger prop, which won't cost much more. You'll likely have to modify your prop cage, but that's just tubing and if you're fairly handy with a welder it shouldn't cost that much to raise it a bit.

I'm trying to get you the most bang for your buck. It's a pig trying to run an airboat in a part of the country where there aren't many because a lot of otherwise talented people (welders, fabricators) just don't understand what they need to do to help you.

Keep us posted.

olf
 
Okay, I appologize!! (I think you all knew I was joking anyway)
Like I said before, you guys have been awesome to me and this site has helped me out more than I'd have ever imagined. I was just poking fun at a few of you cause y'all warned me that airboating can turn into a money pit in a hurry!!!

Is an Alum. radiator that much better?

What am I looking at cost wise for a reduction unit...belt or gear?

Des Moines Boater...what kind of rig do you have?
 
Webfoot,

Man an aluminum radiator will help alot over a standard radiator. As far as a 350 SBC thats a lot of boat for a DD 350 I would run a 2.38:1 or 2.68:1 reduction in your case probably the 2.68:1 and get a good 3 blade prop Whirlwind or Sensenich. With the large reduction you will be able to maintain your optimum hp and torque but still be able swing a good pitch. I would probably go up to 78" to 80" if your rig will accomodate that size.

I run a Ronnie Thibodaux built boat he and Mark aren't to far from one another. My rig is 14 x 7 with ZZ4 350/355 roller motor and I swing a 78" Sensenich 3 blade "K" series wide blade with a 2:1 belt reduction. My boat will run where the big boys run no problem.

With teh right reduction and prop you will be suprized what that SBC will do I think you are moving in the right direction though.
 
Aluminum radiators dissipate heat a lot faster than the others, and as long as you don't run in a salty envoronment (which you don't) they're an upgrade.

Watch the classifieds on here and on Airboat Trader. You might be able to pick up a good used reduction unit .... belt or box ..... for half price or less.

olf
 
Webfoot, I'm on my 4th airboat and the current one is an 11-6 Gillileo with a Lycoming O-320, 160 hp aircraft engine. Every boat I've gotten from Florida had problems overheating. Although my expertice is aircraft engines, I'm sure I can help get yours cooled down as well.

Several ideas have already been given to help without upgrading to a reduction unit. I'd start with a proper double flow radiator, a header tank, increase the pressure to reduce the boiling temp and a milled water pump.

I think you will be happiest if you spend the money now on a reduction unit. Props of any size don't like to turn more than 3000 rpm. I usually turn mine up to 2500 to get on plane for a few seconds and then I cruise at 2000 or less. You've got a lot of boat and a lot of drag to overcome to get it out of the water. The quicker you get it on plane the less stress you put on the motor to keep it there.

Keep us informed.
 
Thanks guys....

I think I'm going to pick up a new radiator in the morning. As far as the reduction unit goes I'm going to watch for one used this fall and go for it next spring.

Des Moines, thanks for the help, I'll be needing more of it soon I'm sure....
 
Webfoot, I'm sure you know this already but you don't want a radiator that is built for a pressure cap .... just an inlet and outlet. Your pressure cap needs to be at the highest point in the cooling system.

olf
 
Webfoot,

Also check your thermostat to see if the guts have been removed if not have them removed or drill out the guts so it will steadily flow and not open and close. If yours currently is a normal working thermostat doing this will help quite a bit. With the guts removed you should run 160-165 F depending on the load.

Just thought that may help you as well.......

Jeff
 
Okay, I just got in from a great afternoon of runnin'.....I tried "water wetter" and it droped the temp down to about 185.....I still would like to know it deown a bit more.

How many of you guys run thermostats with the guts out? I guess I'm curious why you would run one at all then....

Fill me in fellas!!
 
webfoot,

my rig was built from the manufacturer with the guts drilled out. You can just remove it if you want, I think you will find that most automotive rigs run that way due to work load on a automotive powered boat.
 
Thermostat is desgned to keep the water in the radiator long enough to cool down, and in the engine long enough to absorb the heat from the engine.

I just got in from a day of hard running, and even after a long stretch of running almost dry (mud) I never saw the temp get over about 160.

I really think if you have enough radiator and an expansion tank up on the cage to get the air out of the system, a thermostat with the guts left in will work fine.

If you are intent on removing the guts, I think you would be better served to try the restrictor discs offered by Moroso. They have different sized holes to restrict the flow different amounts. A set costs a couple bucks more than a good thermostat and saves you the work of removing the guts.
 
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Posting pics ain't workin for me, but it making a link out of it.
 
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