I have a SBC Sportsman II intake

[SUX 2BU]

And I can't find any information on it. It's dual-plane and that's about all I know. What are the specs for it? RPM range? Would it be like a Performer intake? Better or worse? Thanks!

[SUX 2BU]

Nobody? Not even the folks at Dart? Is this some kind of rare intake or something? Just want to know if it will be good with my combo or not.

[Dart Vader]

It's a common mistake, but that's not actually a Dart manifold!

It's a World products manifold. That should put you on the right track for digging up some info on it! :D

[SUX 2BU]

Really? Oh, well that might explain the no replies lol And World makes the Sportsman II heads too. But the reason why I ask here is because it has DART cast right into it! I have pic too if you'd like to see it. Was there a time where one company made products for the other? Well, it actually says DART II but the script of the logo is the same.

[Dart Vader]

Actually there was a time (more than 10 years ago I'm fairly sure) that we made parts for World. That would be why our stamp is on it.
We don't make stuff for World anymore, but if I can help you with anymore info don't hesitate to ask.

[SUX 2BU]

Ahhh gotcha. Well I'm proud that it says Dart on it anyway! It's actually what kinda spurred me to buy the Iron Eagle S/S heads, since having two Dart pieces makes for a little more wow factor at the show n shine lol Do you recall what kind of specs it had on it? Like what the powerband it was meant for or anything like that? Would it be comparable to the Performer intake? Most importantly, will it work well with my new combo (see my sig)? Thanks very much for the help.

Now that I think of it, it's a Dart II Sportsman. Not a Dart Sportsman II lol

[want-a-be]

"85 Chevy Silverado short, wide, 2wd. Lowered, 60-over 350 with long-tube, small dia. headers, Dart Sportsman II intake, Edelbrock 600 carb, TH350 w/ shift-kit and stock stall, 3.08 rear (I think), 27" tall rear tires. Awaiting installation of Dart Iron Eagle S/S 165cc runner, 72cc chamber, 1.94/1.50 heads, Comp Camps XE268H cam and a spiffy set of chrome Dart valve covers that I painted the logo yellow. Hoping for 375 flywheel HP. "

Loose the edelbrock carb and get a good 600 or 650 double pumper holley carb. Make sure you at least blend the bowls of your new heads. Do some reading first if you've never ported heads. Opening up the pushrod pinch point of the intake runner will help you also. Spend some time degreeing in your cam properly. Might want to consider some 1.6 rockers. If you opt for the rockers make sure to check your pushrod length. Pay attention to the pushrod to guide clearence also. Sometimes they want to touch with the 1.6 rockers.
You might want to consider a lil stall, and some gear. Something between 3.30s and 3.55ish. Ought to be able to hit the 375-400hp mark at the flywheel.

Later, Don

[Dart Vader]

I'm not really familiar with these manifolds so I talked to one of our tech guys about it.
He didn't recall the specs exactly but he said this:

"Yes, it will work. It's a good manifold choice but check the head port and the intake port, the intake might be larger... been a while since I have seen one of those intakes."

Sorry I can't be more helpful!

[SUX 2BU]

Thanks for the replies guys. I've been recommended to port match the heads to the intake, and Chevy Hi-Performance just did an article on gasket-matching an intake manifold. I was told though the heads have to be on the motor in order to port-match the intake to heads. Is that true?

My dilema right now is deciding whether or not to have a shop do the cam/head swa or for me to do it. I have some mechanical ability and reubilt a SBC in high school auto shop but that was 15 years ago! I've ordered "How to Rebuild the Small Block Chevy" by Atherton to get me the details that I've long forgotten about and don't have the experience for. I know the overall procedure but it's the little things I'm not sure of. And then I'd have to buy some specific tools for sure. I'm trying to find a competent shop right now that can do this kind of work and are also capable of degreeing a cam, do port-matching and have all the little tips and tricks that performance buildiers know vs. the general mechanic shop down the street. One shop quoted me $1400 + taxes! He was just looking on his computer though for time allotments based on head gasket changes and stuff like that. So that doesnt really inspire confidence.

Vader, do the S/S heads have enough clearnace for 1.6 rockers without worrying about checking for clearance?

[Dart Vader]

The heads don't have to be on the engine to port match, no, just use the gasket to match it. One of the techs here tells me that you should generally make the intake ports about 10% smaller than the ports on the head.
By using the gasket to match it you avoid getting aluminum shavings in there!

The S/S heads have enough clearance for 1.6 rockers, it shouldn't be a problem, but it never hurts to be careful!

[want-a-be]

One of the reasons they are wanting you to make the heads about 10% larger than your intake is to combat reversion. Not to mention the obvious proper flowing direction.
If you need some direction I'd be glad to help out. I can walk you through most of what you're wanting to do on line. Pm me here and I'll give you the contact info.
I'm not professional head porter by any means, But I have ported alot of heads and for what I charge it is worth it. I've had a few conversations with a guy named Al Neal who is a very high end head porter in the past ( 10-11 years ago ) and he has given me some good tips.

Later, Don

[Awesome Bill]

If you do anything, loose the 600 for the 500cfm. With stock gears and converter, you going to kill the bottom end with that carb and most likely right up to the intakes rpm limit of 5500. Think about top end power, it will do nothing for you. You have a shoe box so mph is out of the equasion and what I get out of this, you want great driveability. Thats what the slightly larger heads will help with but then you go and raise the duration factor and pull the bottom end right back down. Then you put this larger than needed intake, and carb on and you hurt it some more. TORQUE is what is going to make you feel like this thing is getting it, not HP. HP happens with a conversion after 5250 rpm. If you make tons of torque were you can use it, your truck will fly and be able to light up both rear tires from a stop light and be very quick. Stock gears and converters, with heavy truck is a no no for larger parts. jmo

[SUX 2BU]

Thanks guys. I wish I had my intake off the truck so I could set it and the heads up with the gaskets and see where the ports are at. If I do the swap myself, I'll of course check it out as the swap is going to take me a while. If I can hook up with a good engine builder, then I'll ask them to check it out as well. For sure though, smaller manifold ports opening up into larger head ports is much less harmful to flow than the other way around.

Bill, your insight is interesting but if I'm reading you right, it's like you are suggesting to 'choke' my motor quite a bit more than I have the plans for? Torque is awesome for sure, but I do want some kind of reasonable improvement in the heads, cam, carb and intake over stock. I have to free up flow to increase power overall in the powerband, no? I figured I did that well with the convservative heads. I did choose a somewhat largish cam considering the weight, converter and gears my truck currently has but it's a lot easier to plan for gear and converter changes in the future than it is a cam change. I know the 268 adv. dur. cam will make the bottom softer than say a 256 or 262 adv. dur. cam would, but I wanted some kind of HP potential there, even if it is a low revver. I don't really want a diesel-like power curve that stops the fun at 3500 rpm. That's where I'm at now! At some point, I'd like to put in a 2500 or so stall and 3.42s or 3.73 gears with a 700R4 overdrive tranny. That would make better use of the cam for sure, but whenever I would run the numbers for one of those smaller cams, I'd lose around 20 hp with each step and the TQ seemed to be around the same, maybe a little lower on the curve. I kept having 284 and 292 adv. dur. cams pushed on me with 2.02 heads, but I knew for sure that would have created a total dog motor.

[5150skullz]

The world products dart II sportsman intake rpm band is 1500-6500. they are very good intakes, i have a few of them. they are like edelbrock performer rpm & holley later street dominator intakes which are based off the gm z-28 intakes.

[Awesome Bill]

port matching will do nothing for power unless you spin it well over 5500. They want the heads on a dummy then look at the manifold. Most cases 99.9, it is well enough out of the box for this combination. You really won't see any power match porting it in your application. The runners are to big now.

[SUX 2BU]

Hi guys. I was surprised to come on here and see this thread replied to. I was going to make a new topic but since my new question is related to this, I'll just keep this going.

The head and cam work has been done. I saw a gain in power for sure, but honestly, I was hoping it was better. My 2005 Magnum RT felt faster and stronger, although it had a 5 speed automatic too and not a tallish-geared TH350.

I've been considering swapping this intake out for either a Performer Air Gap, Performer RPM Air Gap or a Dart SBC dual-plane intake, which is pretty obvious is either an Air Gap or RPM Air Gap. I feel there is some kind of a restriction on my motor, as it doesn't seem to pull anymore past 4500 RPM and from everything I've read about very similar combo's I should be able to pull to 6000, for sure to 5500.

5150skullz, what you say is interesting: that the Sportsman I have is very similar to the RPM Air Gap. This is the first I've ever heard of that. I thought it was more like the original Performer.

Would I see any significant gains with an Air Gap? It's not that expensive to change to one, especially if I sell the Sportsman. I feel I've got to loosen up the top end to free up HP. I'm hoping to find some kind of 'cork' that'll release some big gains but maybe that's just a pipe dream.

I was also thinking of going up to 2.5" true duals from the 2.25" I have now. That'll free some HP up too but probably not a whole lot eh?

Can anybody think of what I can do to make it breathe better? I can reiterate my combo and the whole package if it helps. I suspect my carb was messed around with before I bought the truck to pass emissions but I really don't know that for fact.

I ran it at the track last fall and it went 14.99 @ 91 in a 4200-4300 lb truck with me in it at sea level. I also put in a 3.40 rear end in the summer. Thanks for any insight and help.

[Awesome Bill]

Your fighting rpm with a hydraulic camshaft, most of these engines like this only make decent power to 4500 rpm. You have to rememeber driveability here. The more air you let in, the slower it gets until piston speed winds up and it starts charging again. But with driving a real world engine of yesterday to an engine today there is no comparrison. Everything is lighter, faster, better flowing and this builds torque with todays engines. Your comparing something that was made almost 50 years ago to todays efi managed systems. Flat tappet camshafts are a thing of the past and won't compete with the roller stuff. If its real heavy and your driving it, go for torque. You can make 600hp @ 5000rpm and I can make 400lbs of torque @ 2500rpm in a heavy stock convertered car or truck and you will loose in gas mileage, performance and take a but whippen if we meet up on the road. The trick is finding a decent middle range, but the bottom end and the upper end will be off. We make all these pullers very quick and responsive up to about 4000rpm. This makes torque, torque is better than hp in these applications. don't believe everything you read about heads and intake. Bigger is not better!

[SUX 2BU]

Thanks for the info Bill. I guess my 72cc chambers don't really help with fast-filling too eh? I knew I should have went for the 64cc...... Ah well. Yeah I guess it's silly to compare to my Magnum's 5.7 Hemi, with it's all-roller valvetrain and probably lighter reciprocating assembly. It would just be nice to have some pull to 5k+. I don't mind if I got some strong grunt down low but I'd like the fun to go up to 5000.

So that all being said and the combo that I have, it would not be wise then to go to the RPM Air Gap? Maybe just a regular Air Gap? Or not even bother at all? I know I have some carb tuning to do to increase driveability. I think the accel pump is either on it's weakest setting or needs replacing. Play with the jets and rods too. And then there's the advance in my Mallory HEI. It's out of the box stock. What I'd really like is to find a local guy who knows how to tune a carb and a distributor.

I know you are a big proponent in not always doing bigger just to get better. Tiny carbs and exhaust and cams is what makes stock motors make stock weak HP and a little torque but having a useable powerband up to 5000 I would really like. What would you suggest?

[Awesome Bill]

You will need a good hyd roller with some valve springs, everything else will be fine and yes you can run the rpm air gap if you would like. You have to remember, even if you were to bring this to me and we put it on the dyno, it would be different in your truck with the exhaust, weight, gear tire, rotational weight is off the chart let alone air filter all the accessories etc. But, your going to make right around 300-325hp properly tuned with 350-370 lbs of torque! The camshaft will allow you to move right up to 5000 rpm and still maintain decent power and driveability.

[SUX 2BU]

Thanks again Bill. According to my timeslip, the trucks weight and the calculator I found on the Edelbrock site, I'm putting about 250 HP to the tires. Figuring for about 22% in driveline loss, that's 320 HP. I initially think I'm down about 50 HP from where it 'should' be but then again, dyno numbers are always misleading. Like you said, accessories and exhaust rob power and those are hardly ever accounted for in say a magazine dyno article. I often wonder if their numbers are more like the 'gross' numbers from the 60's when they didn't account for anything on the motor vs. the net number we have now. Would that be accurate?

I was thinking again on the Air Gap RPM and I'm not sure if the RPM is a good application for my powerband. Perhaps just the regular Air Gap Performer would be good. I would hate to lose more bottom end just for potential top-end that I wouldn't see anyway. I'd love to get another 500 RPM of pull out of it before the nose drops.

[Awesome Bill]

check your stock fuel pump, they are junk, paper an articles can't talk back, ink knows no truth!

[SUX 2BU]

Fuel pump eh? Interesting. Yes I have the stock one on it now. I've been told it's rather adequate even for my setup but perhaps not. I just upgraded my fuel line on the weekend from the pump to the carb with an Edelbrock hardline kit and filter, to an AN-6 hose kit and all the pretty fittings.

[1WILDZ]

I run the same Dart intake for over 10 years now, is a nice piece works real well for street/strip.

[Awesome Bill]

Fuel pump eh? Interesting. Yes I have the stock one on it now. I've been told it's rather adequate even for my setup but perhaps not. I just upgraded my fuel line on the weekend from the pump to the carb with an Edelbrock hardline kit and filter, to an AN-6 hose kit and all the pretty fittings.


When racing dyno's, everyone looses the torque and just looks @ the hp. Torque down low will make your heavy sled run faster. Just to let you know, you will have to make so much power just to see a little because of the application. I don't think anything but a stealth from Weiand or a Performer will actually show you any improvement.
500 cfm and a just a low dual plane intake will run at the least 2 tenths faster and you can shift @ 4500 - 5000 rpm and never hurt anything. Take your cubic inch and X's it by 4500 or 5000 then divide by .3456 then times that by 85%, that is what your going to need. InowImtabout!