Offshoreonly.com - BBC 555 dart vs rpm intake

Offshoreonly.com (https://www.offshoreonly.com/forums/)

- General Q & A (https://www.offshoreonly.com/forums/general-q-20/)

- - BBC 555 dart vs rpm intake (https://www.offshoreonly.com/forums/general-q/337335-bbc-555-dart-vs-rpm-intake.html)

While generalizing, David Vizard pretty much says a big block

500-525HP max torque build, a dual plane with divider cut down is the choice.

525-600hp, he calls it a gray zone. He says either will work.

600hp+, single plane .

We just dyno'd a 588 with an old set of dart 355 heads edelbrock tunnel ram 2 1050's and a cam better suited for a blower and it made over 900@ 6300 840 ft. Lb's torque. From 6300 rpm to 6700 rpm motor only lost 5hp. Tunnel ram is definately the way to go but it gets expensive. If you plan on a single plane intake the best one available is the Sv-565. Sniper would would be a close 2nd...

Quote:

Originally Posted by Black Baja (Post 4451563)

If you dont mind me askin, what were the cam specs roughly? Ive got a buddy thinking about going tunnel ram on some 572s

Quote:

Originally Posted by MILD THUNDER (Post 4451572)

If you dont mind me askin, what were the cam specs roughly? Ive got a buddy thinking about going tunnel ram on some 572s

I'll get them for you tomorrow. The were around 250-260@ .050 .680" lift 114 lsa. We had another cam and intake / carb to try on the dyno bud the carbs were so bad on the tunnel ram we spent the whole day getting the carbs right.

Quote:

Originally Posted by Black Baja (Post 4451563)

nasty

Quote:

Originally Posted by Black Baja (Post 4451577)

Cool, thanks !

Wette Vette's 598 with Dart Tunnel Ram and 2 x 1050's ran on pump gas and went 126 mph in a single engine cat.

Quote:

Originally Posted by MILD THUNDER (Post 4451554)

FWIW.

Sometimes, when you have a 570 inch big block, with ported heads, and goodies, the 30 year old "smaller is better" train of thought, goes right out the window. What applied to 454 build ups many years ago, doesn't necessarily apply to a modern day big CI engine. Back when guys thought slapping on a 1050 dominator and single plane, on a 8:1 truck engine was a good idea, and quickly learned that it wasn't. But, a hot 565ci in an offshore boat, would have no business with a dual plane intake, in my opinion.

here's a 572ci engine, making 800hp at 6,000rpm, and 750+ ft lbs of torque at 4500rpm. You can see what choking the engine with a 850 carb and fairly restrictive GM intake did, compared to a Profiler Sniper jr and dominator. Talking 50+hp gain from intake and carb at peak, and still killed it in torque at the lower end. Going smaller doesn't always mean more torque. Would the 850 carb combo be more crisp in a street car cruising around town with a tight converter , probably.

Good find. Was that an article from magazine or website? I'd like to read up a bit more on it. While surfing and researching the subject from different forums etc I do hear a lot of positive feedback on the sniper jr. I've continplated the tunnel ram with dual carbs and have numerous sizes to try but have to be honest I'd rather stick with the single plane. Would it really be worth the extra perhaps 18 plus hp at the given rpm I will be tuning for?

Tks for your post.

Dart Tunnel Ram on a big cid marine I/O motor turning somewhere from 6000-6500 will make you schit yourself. Will gain from typ vic r / victor 454-r from say 4k and up.

Just like regular intakes, a single plane is not like another single plane and a tunnel ram is not like another tunnel ram.

Richie Zul used to use them alot.

Quote:

Originally Posted by SB (Post 4452065)

Ya I've talked to valako about some here a while back. He of course has tunnel and no doubt makes more power. Ideally I'd like to be propped for 5,600-5,800. So with that said I would like peak hp within somewhere in btwn. No more or no less.

So with that said what would you expect the difference in power to be? If I was gonna be spinning 6,500 plus I'd without a doubt go tunnel. But let's look at where I'm gonna spin the props at. With a ported and matched single plane vs ported and matched tunnel both with right carb set up. How much power diff at 5,700? 18-25 hp Maybe. Torque curve? Gotta call valako tomorrow and get his input also.