Performance Boats Forum banner

1 - 20 of 37 Posts

·
Bouncing off rocks
Joined
·
82 Posts
Discussion Starter #1 (Edited)
I have a 15' aluminum hull w/ delta pad bottom. Running a dominator pump, droop, inducer, ride plate, diverter, set back pump, and sbc. Turns a C impellor 5400, about 5900 on nitrous. GPS top speed w 2 people, fully loaded fuel,beer etc is 70 mph on nitrous.

I have to run a standard rock grate, i run in a real shallow river, 6" - 8' at the deepest normally. Ive tried diffrent ride plate degrees that picked up 1 or 2 mph, but made the boat real loose and not want to turn like i need it to for running the river. I'm running a 2 7/8" nozzle, which seems to give the best performance. Im going through the engine this winter ,

-forged pistons about 10:1
-edelbrock rpm heads, 2.02,1.60, roller rockers
-xm276 roller cam
-weiand tunnelram w holley 450's
-Rewarder OT headers 1 5/8" primaries
-Full MSD igntion, locked out MSD dizzy

Looking for 450-500 before nitrous



The boat seems to ride low in the rear when on plane, but cavitates easily in anything more than 6" chop. I know i need a loader, but thats not really possible. Is it possible to get into the 80's with this configuration? Anything else i can try as far as setup?
 

Attachments

·
Registered
Joined
·
550 Posts
How big is the engine? I would try stroking it to a 383 if thats an option, then try a larger impeller...
 

·
mo balls than $cents$
Joined
·
11,734 Posts
put a single turbo blow thru set-up on it and it'd crank out 600+ with the same longblock:)bulb
 

·
Bouncing off rocks
Joined
·
82 Posts
Discussion Starter #4
its a 350. I killed my budget with the heads,cam, oil pan, intake setup etc already. I wanted to stroke it, just cant afford it. I'm hoping to be able to turn an A or A/B around 5000 without nitrous. I'm just wondering about making my setup more efficient, as thats a hell of a lot cheaper than buying horsepower
 

·
Resident Ford Nut
Joined
·
10,079 Posts
its a 350. I killed my budget with the heads,cam, oil pan, intake setup etc already. I wanted to stroke it, just cant afford it. I'm hoping to be able to turn an A or A/B around 5000 without nitrous. I'm just wondering about making my setup more efficient, as thats a hell of a lot cheaper than buying horsepower
That might be a tall order for the 350". To make 500 hp with a 350 that's 1.41 hp /cu. in. It can be done but it's a very tall order to do it at 5,000 rpms.

I built a 418" Ford for my dad. It made 500 at 5,000 and 525 Hp at 5,600 with a TR and 450's. That's 1.26 hp/cu in. I think you're going to either increase the stroke of the engine to get the 450-500 at 5,000 or your going to have to rev it much higher.

Sleeper CP :D
 

·
Registered
Joined
·
2,234 Posts
If I may be so bold...All the horsepower in the world will do you no good if it won't stay hooked up, if it cavitates now, there is something wrong with your setup, I would suggest an inducer on the pump to help, and check the amount of rise or fall from the pad to the intake cup (may need to be shoed if way off), only then would I say more HP is in order.

We have an aluminum 18' hull with a 377 SBC and run an AB impeller (ss) with an inducer at 5800 RPM and it will run 75 MPH with three people a cooler and a full tank of fuel......It can be done without a loader and with a heavy duty rockgrate.

GOT pics? Aluminum is the new fiberglass:)devil

GT :)hand
 

·
Registered
Joined
·
2,234 Posts
I run a SBC with an @ 4200 rpm. It's all stock. Not sure if this any help to you or not.

IMHO you need to free up some RPM, small blocks like a little more revs, you have not even tapped into peak torque until 4,600 RPM.

GT:)hand
 

·
Bouncing off rocks
Joined
·
82 Posts
Discussion Starter #9
GT - The only time it cavitates is in chop, on smooth water it hooks just fine. i have a flat bottom delta pad, not a radius. I have a DPS inducer installed as said earlier, helped a ton coming out of the hole. Like I said, it runs 70 now with a stock goodwrench crate motor.

Im looking for advice on hardware setup, not hp. Is there anything i can do to my rock grate to load it better, but not jam more rocks in it when i run shallow? What can I do to lift the transom higher out of the water?
 

Attachments

·
Registered
Joined
·
2,234 Posts
GT - The only time it cavitates is in chop, on smooth water it hooks just fine. i have a flat bottom delta pad, not a radius. I have a DPS inducer installed as said earlier, helped a ton coming out of the hole. Like I said, it runs 70 now with a stock goodwrench crate motor.

Im looking for advice on hardware setup, not hp. Is there anything i can do to my rock grate to load it better, but not jam more rocks in it when i run shallow? What can I do to lift the transom higher out of the water?
15' boat = a little dangerous at ultra high speed, that being said....I think you are in need of a droop, this will lower the thrust angle of the propulsion and increase transom lift while enhancing the overall handling. The reason for the ass heavy attitude IMO is due to the boat being short (read; "bow light" boat) the factory style rock grates do offer pretty good protection (finger type), but you can get away with a plate type too, the openings are actually smaller than a finger grate and much stronger, that would be the direction I would go, we have run these for several years and yet to have a rock related failure due to the loader. Let me know your thoughts...

GT :)hand
 

·
Large Member
Joined
·
679 Posts
IMHO you need to free up some RPM, small blocks like a little more revs, you have not even tapped into peak torque until 4,600 RPM.

GT:)hand
I meant to say A impeller. Oh well. 4600 would
be nice, but my boat is all stock. I was trying to throw out a base line number. not too many people on the boards run small blocks.
 

·
Registered
Joined
·
2,234 Posts
I meant to say A impeller. Oh well. 4600 would
be nice, but that would mean HP.
If your getting 4200 RPM with a baby Chevy, thats a good running motor, I would put "B" cut in that rig and see what happens....Just my opinion and not my $$$$$$$$.

GT :)hand
 

·
Sit N' Spin
Joined
·
1,423 Posts
No replacement for displacement. Run a big block. :D

Just my $0.02
 

·
Registered
Joined
·
2,234 Posts
No replacement for displacement. Run a big block. :D

Just my $0.02

A big block in a 15 foot boat is like a blower for your Tercel :D Unless of course that big block is made aluminum :)devil

GT:)hand
 

·
Bouncing off rocks
Joined
·
82 Posts
Discussion Starter #15 (Edited)
15' boat = a little dangerous at ultra high speed, that being said....I think you are in need of a droop, this will lower the thrust angle of the propulsion and increase transom lift while enhancing the overall handling. The reason for the ass heavy attitude IMO is due to the boat being short (read; "bow light" boat) the factory style rock grates do offer pretty good protection (finger type), but you can get away with a plate type too, the openings are actually smaller than a finger grate and much stronger, that would be the direction I would go, we have run these for several years and yet to have a rock related failure due to the loader. Let me know your thoughts...

GT :)hand

i already have a droop installed, along with inducer,ride plate, and a diverter. This boat had a 14:1 496 bbc in it when my dad owned it and he ran it in the NDBA midwest, it ran high 90's, with a best of 101 with that in it. I sold that engine to be able to afford to purchase the boat and put the small block in it. He said it was pretty sketchy at that speed, I'd like to be able to run 80 - 85




what do you think about adding wedges to it? you have a pic of the other type of rock grate youre referring to? i have a legend intake, will it fit and where can i find one?
 

·
Bouncing off rocks
Joined
·
82 Posts
Discussion Starter #17
i need an aluminum hull. a fiberglass hull wouldnt live 1 day on the river. Plus, this thing has sentimental value. Its been in the family since i was in junior high,and im 27. dont think i can ever sell it
 

·
Lurker
Joined
·
1,417 Posts
Definatly can't comment on your boat set-up as I am more than green in this area. :)sphss
I will say that if/when you get back into that engine, a little port and chamber clean-up, a point to a point and a half of added compression (mill heads, change gaskets ect.) and about 20 degrees more duration on both sides (along with .100 or so more lift) would wake that thing right up!
Should easily make your power goals.
IMHO going in this direction, plus some set-up/bottom work from some of the shallow river racers and that thing would probably go faster than it ever should!
 

·
SLOW MEMBER
Joined
·
470 Posts
You can go fast with a small block, just have to get your combination right. It sounds to me like somthing is not set up correctley with the pump. My boat is a delta pad boat and it is 18 feet long and made out of fiberglass. I am sure it is heavier than yours, as it has a stereo in it, subs and all. Last time out we went 86 with two people in it, full of gas and a full cooler. We were turning a BC aluminum impeller (that has been cracked and welded a couple of times:)devil) 5900-6000 rpm's. That is not many more rps's than yours, but with a faster speed.

Some things I did for improved speed.

*Check that the droop is not leaking water out the steering nozzle joint.
*Put a loader in the pump, you are probably cavitating. I changed to a rock grate one day and we went waaaaaay slower.
*Play with different shoes, and even try removing the ride plate.
*Try a few wedges.

I would only do one thing at a time, or you will get lost:)sphss

Ryan
 

·
What the Hell is That?
Joined
·
1,633 Posts
I too run a SBC (327 060 over) but mine is a mild SBC 144 blower and all.

I had heard droops were for big power boat's plus light boats.

If I added a Droop to a heavy lay up Boat would it even do anything?
 
1 - 20 of 37 Posts
Top