A 351w (stroker?) from scratch...

Joe, what kind of ignition are you running. I tried to look back and see in the post, but I didn't find it. Reason being, on my new rebuild, i noticed that I was not getting the punch I was expecting...I found it in the ignition/distributor. A little tweaking and it's got a holeshot that's pretty stout. 0 to 40 in 6 sec. That's with a crappy stock Michigan 13 13 or OJ (I forgot). Anyway, give me your rundown on the motor again. I know you were changing cams and compression and other stuff. What did you end up with?

I don't have the cubes you do, nor the roller cam. I still don't know your cam specs. I ended advancing on the high side of 10 degrees, with about 35 degrees total advance (took some spring changes and some grinding of weights). With your compression, heads and cam, I would imagine it will like a little more timing as well. I think that I am leaning toward the 541 as well, but I don't want to turn too many RPMs. Which prop and carb are you getting?

The new prop is an acme 431 (13x13x.080). The carb is a 650 cfm bg marine demon mechanical secondary, I still may keep the 750 cfm holley vacuum secondary if I can get it tuned better (so far I have only switched the springs on the vacuum secondary and have a long way to go) but I borrowed a 650 cfm barry grant when I had it on the dyno and it was a considerable improvement over the untuned holley. My cam specs are 224/230 at .050 114 seperation, and .533/.544. Gottaski probably has it right on the timing most 408's that have been documented in the various mags ended up right at about 34 being optimum, thats why I started at 8 since I didn't have time to play with it yet. I am hoping not to have to get into the springs of the freshly curved dui, but it is possible I will need to reduce the mechanical advance spread to really get it to jump out of the hole.

-Joe.

racintj,
    I did get some a couple dyno pulls, and will put up the hp/torque curves when I get ambitious enough to type in all the data into excel as all I got was printouts.

Hopefully we are about at the end of this process, I have installed the 650cfm mighty demon marine carb and the new acme 431 propellor (13x13, .080 cup).

Out of the box with the timing at 10/34 she runs in the low 4900rpm area with me in it. I am pretty happy with that. I dont know what the actual top speed is, the perfect pass hits 47 at about 4450 rpm and then stays at 47 up till 4900 rpm, where it flirts with 47.1. Both airguides are pinned tight by 4650 rpm but are less than accurate at that point. My guess is it is breaking into the 50's slightly.   

My intial timing is a little low for optimal hole shot, performance distributors wants me to sent it back to be recurved I am reluctant to lose it for a couple days but dont want to mess too much with changing the settings on the mechanical secondaries and squirter shot sizes until its right, it has a great holeshot but a little inconsitant and with a small bog. I think it can be tuned to an unreal holeshot.

Quick notes on the carb, there is no choke or choke tower, so far I dont miss it with no adjustments and the same set of cruddy plugs I have used throughout the break in/dyno process it still starts first bump after sitting overnight and idles as low as the damper plate will allow right off the bat. I May change my mind on this in the fall when it is colder out.

It is a mechanical secondary carb, currently the secondary is coming in at about 2900rpm (32 mph). I am going to try to put that off till 37-38 mph to make slalom ski speeds more steady with the perfect pass, as it doesnt currently hold as steady as it used to. There are also settings on the perfect pass I could change to affect the damping rate but I would rather not screw around with those.                                 

So a distributor recurve, some adjustments to the secondaries, and a bunch of plug chops and jet changes, then one last oil change at 15 total hours where I will switch to synthetic and hopefully we can call it done.


-joe.

Good morning billy,
     You can change how far into the throttle rotation the secondaries come on with changes to the linkages between the two both up and down, there are also progressive and direct linkages. If it opens the secondarys later in the throttle rotation it would be good. alternately it could open them earlier and that wouldnt be bad, but to have have them opening right at slalom speeds makes it touchy to hold speed.

The difference in props between yours and mine is substancial. (ignoring the fact my prop turns the wrong way) My boat came standard with an oj 13 x13, and the recommended acme replacement for that 13 x 13 is either a 540 which is (13x12) or a 542 (13 x 11.5). If I turn the 540 equiv I get about approx 1mph of speed for 100 rpms at most planing speeds although things get sketchy at the high end with that 1 to 100 relationship. The prop I have now is the 431 which is a big cnc prop like the 540 series, it dropped my rpm by 250 at 21mph (1850), 350 at 36mph (3300), and so forth till my speedos become unreliable. My horsepower curve did peak at 4700-4800 with this setup (mostly cam limited, maybe manifolds/mufflers a bit) so since I am into the low 4900's I could increase another half inch maybe if I get a lot more out of tuning an inch but then we would be affecting holeshot significantly. My gut feeling is my current acme 13x13 is about equivilent to your 12x14 in regards to speed vs mph.

My motor in your boat would need a bigger prop but I have 2.5 more feet, 3 more fins, and 50 percent more weight than your skier with only 23 percent more motor displacement.

"Quick notes on the carb, there is no choke or choke tower, so far I dont miss it with no adjustments and the same set of cruddy plugs I have used throughout the break in/dyno process it still starts first bump after sitting overnight and idles as low as the damper plate will allow right off the bat. I May change my mind on this in the fall when it is colder out."

Joe, you won't need the choke. I run a jet boat with Holley with no choke, I ran it into November last year. You just use the accelerator pumps for your choke, pump the throttle a few times before starting, a few more times in the first 20 seconds and you'll hold idle OK.

Well here we go on year two of the stroker build, rebuild, and tune process.

The new Hiteks are in and fit up well


they were custom made to clear the tall valve covers


they were also ordered to match the exhaust ports of my aftermarket cylinder heads, in this picture you can see the difference in size between the standard head exhaust ports and the size of the ones on the hiteks



I am also changing the cam this year and while it is apart I am using the opportunity to port match the intake manifold as last year I ran out of time so I assumed close enough.

There is actually a significant amount of material that needs to be removed as seen here



Here is the right tool to start the job



Do not attempt to do this with a grinding stone, a good carbide bit and a die grinder is key as is eye protection.

First one looking good


Second one not bad either



The third one went ok, but things were getting sloppy on the fourth one

first I let the grinder jump across the gasket surface not one but three times



and then disaster hit





Well that was about it for today, tomorrow I have to get the other side and go to the welding supply store...

Joe, I didn't know what to say after your last post...glad you're back on track! Was the RR roller cam as big of a deal as it was with mine? I sure wish I had pulled that off.

Mighty ambitious to be doing a stringer and engine job + keeping up with life and helping friends! I am humbled.

There is no RR Roller Cam for ford either, this stroker is std rotation which involves a new transmission, new drive shaft, new mounts, and a new prop so its still a pretty big deal.

Oh and its a stringer floor carpet, engine upgrade, stereo upgrade and tower install this year







Trying to be done by June 1st... going to take a bit of luck.

TRBenj wrote: Greg, Joes stroker is a lefty- so no RH roller issues. I think he's got plans to mate a 1.23 to it for the RH prop. Joe, Im eager to see how performance improves with the new cam, porting and Hi-teks. Should be very interesting! I love the red powedercoat, by the way.

I am interested myself, its too bad I will be changing so much at once esp. with the trans and prop to really know what, if anything, has the greatest effect.

I got a few other enhancements ready this year too but at this point I am most worried about the floor and stringers.

i look at every picture in detail and do say that you do nice work, it seems that everything is coming along nicely

the things you guys gotta do to keep up with a bowtie lol

Joe...you go boy, how many of those girls are going to Gl with you? And what boat is that motor going in? Is that paint or powder on the hi-teks whatever it is, it looks good!

keep up the good work, and you will be smoken Reid soon!

Looking good Joe...nice touch with the ARP's in the intake!

And a bunch of cuties at your party, but I bet thay all have funny accents?!!? LOL

heck with the stroker, tell us about the bonfire lol, had to scroll past the pics this morning....it was a wife thing