My quest for 60 MPH
 

Info:
85 Four Winns Santara 21.5 cuddy cabin boat.
Engine: 5.7 GM.
Drive: Alpha w/drive shower.

The bottom end is a 350 Goodrich motor. I have upgraded to GM performance heads. 64cc, 200cc intake runners, 2.02 intake, 1.90 exhaust. The cam is a comp marine 491/490 grind. I have a weiand single plane manifold and have changed to a 750 edlebrock carb.( fat jetted ). I am running the Mallory MAL9-26000 marine system from ebasicpower.com. My issue is I did most of these upgrades this year and have not gained any top end speed? I am turning with a 14x17 prop 4600rpm @ 47MPH. I prop up to a 14.25x19 and loose 400-500 rpm and no speed gain. I prop up to a 14.25x21 and loose 400-500 rpm and gain no speed. I would think I would loose 200 rpm with the prop changes and gain some speed. Over all the 17 gives me the best hole shot and best top end. I'm willing to sacrifice some hole shot for top end but I don't see it. I would think I gained 50-75 HP by changing the heads and cam. The original heads were the stock Goodrich iron 76cc head. And I am checking speed through GPS.

From my understanding the distributor has a TA of 28 degrees. Is that limiting me on the high end? I see most performance SBCs are running 30-34 degrees TA.

Any ideas??/

Thanks Mike.

What Dist are you running. And yes thats prob killing you power and fuel economy. Any good 5.7 should make 275-300 hp. That should be 55+ on that boat.

Chris

Two things:

The hull is limited due to displacemt

The drive is buried nice and deep.

I threw a bunch of power into a 1975, 18' searay and I hit a speed wall because of those two reasons.

I am running the Mallory MAL9-26000 marine system from ebasicpower.com.

Are you sure you have a good understanding of how your advance operates?

I would put 18 to 20 degrees in at idle (initial timing) and have a full 34 degrees or so all in by 2200 rpm or so.
The boat will be happier at the dock with more initial timing.

18-20? I think I have it set at 8-10 right now at an idle.

Yes, 18 to 20 initial.
You will have to limit your advance to 14 to 16 to get your desired total.

Got ya, makes sense. So starting at 8-10 I may only be hitting low 20s for TA.

The single plane intake is hurting your setup not helping. Sub 5000 rpm SBC's need a Dual plane. I did a back to back test on an old motor years ago. RPM Air Gap to Vic Jr, same day, conditions, swapping to the Vic Jr lost me 3 gps mph top end and ALOT of midrange. This was on a 355ci 10-1 AFR head, 226/230 roller, with dry exhaust spinning 5800-6000 Rpms. Needless to say I went right back to the Rpm air gap. Your giving up a lot of power everywhere thru the rpm band with the single plane.

Verify 34 degrees advance at WOT. This is what you need. Not familiar with that systems advance setup.
If you are now at 28*, your leaving a lot on the table.

Changing power and props is not a quick fix. A lot of testing and time is required to dial it in. Turning only 4600, you are not in the power and, hence when you add pitch and drop rpms you do not gain speed. Prop for 5000-5200 I would think with that setup. What type of prop?

I personally think that unless you plan to go down a waterfall the speeds you want may not be in the cards. That is a lot of boat and considering the size of the engine - you maybe at the limit around 50 mph. That's only my opinion. When you start messing with props, effecting engine rpm's to a maximum- you may get the speed up but are really taxing the engine, drive etc. At the end of the day you may have one heck of a pile of broken engine/drive stuffs. I know in our home mama wouldn't be too happy!!!

3pointstar

Everything seems to be holding strong on drive. Oil is changed often and always a nice clean blue. I have gone back and forth with a edlebrock performer duel plance and the single plane. Have not noticed any difference on that. But maybe once I dial in the timing it will come into play. I will verify the 34 TA on the timing.

Thank you.

What are you using for exhaust? Have you done a compression test what are your numbers if you have?

What heads are they ? I don't know of any GM Performance 200cc heads. The Large Vortecs maybe ?

Which Comp marine cam ? Your lift doesn't lead me to one.

That intake is doing you no favors as Ryan pointed out.

Most Goodwrench motors have crap for compression with 76cc heads. What is your Compression ? Edit: just re-read and see you mentioned 64cc, Please double check and provide us with the cyl heads Part#. Reason for asking, a low compression like 8:1 won't like much of a camshaft.

As far as my call right now, sorry if this hurts but I am still here to help, going by your innacurate listing of parts (I haven't mentioned the impossible 1.90 exhaust valve yet - ooops, just did) and possibly poor choosing of parts, that you may have outdone yourself by buying first and asking later vs asking first and buying later.

Let's see what accurate info you can give us and what we may be able to do to help.

There are a good amt of small block guys here with a lot of hands on experience, so you picked a good place to ask.

Running Merc stock exhaust manifolds with wide open thru hull. Compression test is consistent across all 8 cylinders. Thinking they were at 140ish. Motor has 212 hours on the bottom end.

Understood. Can get the actual part number once I get home. At work right now. And any info is good info. You won't hurt my feelings.

I think SBI nailed it on the compression . Those numbers are way low.

Found it in my email.

Cam: 249-XM-CL12-240-4 Jegs part number.

Heads: Sorry, they are 210cc runner, 64cc, 2.02 intake and 1.60 exhaust. Brand is pro-comp performance.

Compression was 160ish. Sorry for the bad info guys. Did not realize how involved this would get.

I think your combination is killing it. The cam is really too big for those heads on that displacement of motor. The intake velocity is no low making for a sluggish motor. Slap those heads on my 413 and the intake velocity would recover, but not be as good as my AFR 210. A smaller cam maybe the 212/218 or 218/224 max would have been a better choice on those heads. A standard performer with no plenum notch and barrels isolated between the left and right side of the manifold would make for much better response. Cranking compression sounds right for that cam and those heads. Probably around 9:1 with the 64cc chambers. Just my 2c. Good luck. Oh yeah, bump the timing, that will help your part throttle response as well. Also verify TDC is 0 on your balancer. I've had it where my old motor hit a weird wall and I then realized it was the ring on the balancer slipping. No pinging and no hard starting on mine, I happened to find it after I pulled the motor for something else and saw the rubber shifted.

Thanks guys, going to go after the timing number one. And then swap out the manifold after I play with timing back to the dual plane. The motor does run strong the way it is. I just think it should run better. Feel like I should be able to crank up to at least 5500RPM. My first attempt at going faster on the water. I am seeing it takes close to perfection and more planning before getting a bunch of parts and slapping it together. I did read a post that every mph on the water is earned by pure HP. I am a believer in that!!!

if your ig timing is low it will be a mutt.160 cranking compression with those heads will like 34 to 35 deg total advance all in by 2800 rpm.verify timing,then test with the 17 pitch prop.let us know the results.

COMP Cams#249-12-240-4
1600-5800 RPM
Duration Advertised: 270° Intake / 286° Exhaust
Duration @ .050'' Lift: 226° Intake / 236° Exhaust
Valve Lift w/1.5 Rockers: .480'' Intake / .489'' Exhaust
Lobe Separation Angle: 112°

=================================

Should have figured on the cylinder head. Pro-Fraud / Jumk.

Anyway, 210cc heads are for super stout 383's and bigger.

Your 350 better have close to 10:1 compression (Min of 9.5:1) with that cam and cylinder heads. Heads still wouldn't be ideal size wise......but.........won't totally kill you.

Intake, we went over - throw that out.

Edelbrock carb - size is fine. Many out of the box have had issues with secondaries not opening all the way..you need to verify this.

Exhaust - you'll hear many comments on this. Not a good choice with that cam either. A smaller cam, which will be better for that engine, will be better for that exhaust.

Did you up your fuel system ? Get rid of the antisiphon valve and get a Holley marine mechanical pump. Rest of fuel system should be okay for your power levels.

Flame arrestor. Minimum of 9x4.

Timing. 34 Max should be fine. Start with 32 to be safe.

===================

There you have it.

Again, a bunch of flyin small blocks around here. Even upper 60mph mild ones to 80 and almost 90mph wild ones.

=========================

Since you said you can take the criticism, I will say, your parts combo really kind of sucks.

Let's see what we can do with it without changing big things and/or big labor intensive ones.

Sometimes.

Example: put 330HP in a 22ft Velocity and you'll hit 70mph and change. Most other small performance boats will get into low - mid 60's.

Also, there are many boats out there that will not go faster than a certain mph no matter what power you put in them.

hp is a huge factor.
Prop is a huge factor.
The boat itself is a huge factor.

Ouch, LOL. Yes, those were cheap heads.

Carb: Yes, went through carb and adjusted it. Floats were way off.

Fuel: Yes, went to a 110 GPH pump regulated down to 6. And got rid of the anti-siphon long ago.

Flame Arrestor: Yes, had room for a big K&N marine set up. Don't remember size exactly but larger than 9x4 for sure.

Exhaust: Looking for a little bigger boat so not going to spend the $1000-1500 I have seen good exhaust go for. Going to stick with what I have.

Timing: Will be the 1st thing I do to see what happens when set up. Going to pull the distributor and go run it at the local bench to see what it's at for sure.

Again, thank you for all the input guys!!! Your knowledge is helping!!!

Pic shows what a 85 4Winns Santara looks like.

http://tenwheel.com/imgs/a/a/p/y/a/1...port_4_lgw.jpg

1988 Four Winns 210 Horizon - 383ci 68mph radar . :cool-smiley-011: http://i1243.photobucket.com/albums/...edeep/slap.gif

http://i1243.photobucket.com/albums/...09058b3d83.jpg

So what is the economical fix SB?

Install some Vortec heads and a daul plane intake and than go to a smaller cam to work with the compression and exhaust he has.

And of course still observe the secondaries and correct the timing.

1st question: Do these Procomp 210 heads have Valvesprings for Hydraulic Flat Tappets heads ? Most heads this size are used with solid cams or radical HR cams.

2) F*k yeh on the intake ! Performer RPM is even much cheaper than the Air Gap....if $$$$ is to be saved.

Tune, tune, tune. So many people are up there own azz when it comes to tuning (engine + boat) that many boats are slugs because of this.

99% of performance enthusiasts (all motorsports) are bolt on and go. And then obviously disappointed.

=====================

So.....hopefully the OP swaps intakes and then tunes correctly.

Pointing out another obvious - the look of that style boat puts up a big red flag that it will be hard to get decent mph out of it.

Speaking of which, it's an 85. Anything that old should also put up a red flag about possible water issues !

SB missed his original post of what boat it was in but now seeing this even if it doesn't have water I am quite sure that model is rather heavy and inefficient in bottom design,

If he does get the motor to it's full potential I think pushing that boat hard will take that old Alpha 1 right out .

Did OP ever tell us where he is??? (Present best speed)

Yes. It's in the first post. 47mph.

Sorry, I missed that.. I bought this same boat new in 1987... They renamed it 215 Sundowner. I ordered it with a 230 HP Mercruiser( 305 Chevy with a Quadrajet). It ran 43-44 with stock power and bottom paint. In 2007 I repowered it with an Indmar crate motor and stock exhaust(Vortec Chevy 350) they stated roughly between 300-320 HP. Hit 53 MPH on GPS.. Only other change was that I had to go up in pitch on the prop...
That said: I would not want to go faster in that hull... Still a great boat after 27 years...

Alright, did some digging as I remember a few rag mags beating the crap out of stock Goodwrench 5.7's.

Stock compression is 7.8:1 with it's 76cc heads.

For them to get 9.0:1 compression with 64cc heads they needed to use .015 headgaskets.

Here's a good article om modifying this motor:
http://www.corvettefaq.com/c3/goodwrench/gm3502.htm

Awesome cause you can give the OP great info - especially propping and what not.

The alpha will be fine on that boat up to 300 hp. 350 if you take it easy out of thew hole

Chris

Heads are way to big so is the cam as well as crancking compression possibly do to the cam and lazy intake flow. IK brodex smaller port version would be best and a cam with less at .050 duration and about .500ish lift. Raising the X dimension possibly a big help also

I moved the X up 1 7/8" on my Four Winns and it made a tremendous difference in speed and handling . When I built a stock engine to put back in it to sale , the boat still ran extremely well and the first guy to test ride bought it .

I have the following head gaskets on the motor:


Fel-Pro 17030
PermaTorque MLS Head Gasket •Small Block Chevy Marine
•Gasket Bore: 4.125''
•Compressed Thickness: .039''
•Compressed Volume: 8.7cc

Small Block Chevy Marine

Have the distributor out and taking it to see what its doing tonight. (where its currently opening up and how far)

After reading:

Here's a good article om modifying this motor:
http://www.corvettefaq.com/c3/goodwrench/gm3502.htm

I see I bought the wrong head gaskets too. Should have went with a thinner one. Wow, I do have a bad combo of parts. Will always ask before I start buying from now on for sure!!!