600 ci NA build
 

I see it seems like a lot of people on here are in the process of building or have built bigger CI NA combos. We are in the process as well of building 2 600 ci NA combos for our boat. Just curious of what a lot of guys combos are and what kind of power they made.

Build
 

Ours will be 600 ci conventional style cylinder head, 4 stage dry sump,cast intake single throttle body in EFI. We are looking to make between 900 to 950.

What drives do you plan to use?

We have #6 drives.

Pump Gas??!! if so..950 seems a bit of a "stretch" to me??

We run mixed pump gas. Comes out to be around 98 octane

What bore and stroke combination will you use and the targeted max RPM?

They will be 4.605 bore and 4.500 stroke. For those short blast we will turn it up to 7400 ish. We have a 32ft Skater so it accelerates extremely well.

Off the shelf cam or custom........:angry-smiley-038:........its a joke.........but are you going to run a large journal cam or std. sounds like a nice build

Big base circle deal with roller cam bearings. Jesel 904 lifters with the .820 wheel.

950 is probably the ceiling if you nail the setup. My old engine is close to that but 12.5:1 588 dry sump with a tunnel ram and 2 4s we spin it 6800 but the cylinder heads are maxed and what’s holding us back (dart 355cnc fwiw). New engine we have 2 sets of heads to do some rnd on the machine with to see what’s going to work the best.

Ive done a fair bit of combos with the 588 trying for the most power and tq including 4 cam swaps, intake and carb swaps cam timing adjustments ignition timing adjustments ect.

my personal opinion with a single carb it is going to be hard to hit that number. Atleast we struggled to get there, tried a sv632 Intake and a sv565, as well as a victor. With a quickfuel 1150 and a Holley ultra 1250 all left a good bit on the table compared to 2 4s.

It will be very interesting to see because our drag race stuff with 13.5.1 stuff makes over 1120. Witch this will have less cam and compression but still a 380 cc + head. And of course this more of a endurance build.

What kind of cam specs are you thinking? And to turn 7400 you’re going to have to be pretty big not saying it’s not possible but maybe your definition of a big cam and mine is alittle different. I’m high 270s on the Intake 290 on the ex about 800 lift On a 113. Made peak Hp 6700 on the dyno (again heads are limiting me) Standard base circle and it’s pretty hard on .843 lifters, I get about 30 hours out of a set which I check every time the boat is used. At 28-30 hours they start to move around and i replace shortly there after.

Still up in the air on the cam but it will be 60mm roller bearing deal. I would feel sure yours would make more steam with more head. I take it you also have small bore engines

Is there a reason / restriction to CI. 632 would be much easier to obtain your goals.

632 has a really bad rod to stroke ratio for endurance in a 10.2 deck block.

I understand especially for endurance. This is a good thread and a little out of the norm so there will be much gained and hopefully results in you ending up with your needs.


https://www.offshoreonly.com/forums/...ition-box.html

Just a thread for chits and grins. Not comparing just throwing it out there for some reading material.

well being on a 60mm you’re talking totally different ball game. As well that’s going to be the same direction my new motor is going. It’s 4.560 bore currently and if you believed everything you read on the inter webs those heads on a 580” motor will support 1,000 but I don’t believe it. Maybe if I sent them to fultz or someone.

But moving on to your build I would make sure your induction package with a single 4 is spot on atleast to hit 950 900 is probably obtainable pretty easily especially for your target rpm.


Can i ask what Head youre looking to run?

The top end will be a Dart based head 380 cc intake runner minimum. Will know the exact head after the PRI show this weekend. It will have jesel rockers aluminum intake and stainless exhaust. It's definitely going to be a Max effort deal with endurance a key part of the build.

What machine shop is doing the cam tunnel and lifter bores, if you want to share.

Sniper X (375cc ) has gone 1200+hp
https://www.profilerperformance.com/...ree-heads.html

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Just had to add something so I can subscribe to this thread. :)

im partial to a set of brodix headhunter 383 non MC that I’m going to try. I bought them last year on a sweetheart deal when someone put a deposit and never picked them up.

Kind of wanted to try a set of SR20 heads but you have to draw a line somewhere. Kind of have to plan your entire build around those heads.

David Nickens is doing the hole build.

cool stuff. Top notch!!! $$$ but at least your in good hands. keep us informed along the way. If I were to do over I'd go larger ci and eliminate the SC's on 548's. Boat is to heavy for twin 565 NAs. Good luck with everything and let us know any new thoughts after the show.

what is the bore&stroke combination?

It's 4.500 stroke 4.605 bore.

I had 383MC brodix 276-284 on 114 with 750 lift 10.1 kinsler injection made 960hp 6800rpm dry sump 6stage standard cam core and 842 lifters.

Very nice that's good horse power for sure.

Well just got the call from David nickens. We are going to us the dart Pro1 20 451cnc head.Hmm lol

Be carful might hurt the low-end torque a bunch just saying airspeed will be down at low rpm. What boat you putting them in? My apache suffered planning off with the big heads on it.

We’re these also 600 ci? Just out of curiosity were you also pulling a vacuum on the motor? My 4 stays dry sump couldn’t do it, we tried on the dyno just wasn’t happening.

Not really concerned about getting on plane. We have a 32ft Skater and also has 2 speed Trans missions in it the boat rolls over as soon as your role in the throttles it's crazy. The boat it rarely under 3000 RPM.

Yes with 600. I block the lifter valley I only pull vacuum in the pan I didn't want to starve the valve guides of oil. If I want it will go high 20s on the vacuum in the pan but I regulate it to around 12" Running auto verdi pump with oil air separator on the back of the pump. The oil pan has dividers at each main cap..

hell yes, I would go for more cubes though

someone on YB said SR20s have less CSA than your heads. The extra volume is due to port length.

Can only us a 10.2 Deck Block because we all ready have the headers. We all ready have to have new tail pipes. Just trying to be a little different by not having a SC combo witch we just took out of the boat. Anything in the 900hp the boat will run faster then we care to go in it. About 6 weeks ago we were just out playing around in it and run133 In less then a 1/2 with 3 people in it.

That was me on their rite? Was I talking about my 16 big dukes? The short side of the runner is the same length from my big dukes to the 383mc 24* heads. I think the sr20 is to big just my opinion unless its a max effort deal.

Are you putting 60mm cam cores in these engines? What lifter combo you going with?

Post 14 - Still up in the air on the cam but it will be 60mm roller bearing deal. I would feel sure yours would make more steam with more head. I take it you also have small bore engines

post 10 - Big base circle deal with roller cam bearings. Jesel 904 lifters with the .820 wheel

[QUOTE=Single cat;4597955]Still up in the air on the cam but it will be 60mm roller bearing deal. I would feel sure yours would make more steam with more head. I take it you also have small bore engines[/QUOTE

Don’t it is possible to get too much steam or head...