Mopar 337 intake port question

I have a chance to get a new 337 intake. My question is will the fit TF240 heads? Meaning port size.

Fundamentally the 337 has MW sized ports.
The heads can be modified to match, but as both items come “ootb”, they aren’t a match.

The 337 is a great intake so if you have a chance to grab one I'd do it as long as the price is fair. It would be a better match for TF270 heads. I made over 800 hp with a 337 intake on my 514 dyno engine. That engine had MW ported Indy EZ heads. The 337 intake worked a lot better than anyone expected. It is a low profile intake so it doesn't look like it can make 800 hp but it did.

I don't plan on buying new heads. These 240's are new and together on the car. It was this intake or a ported torker 2 I was looking at. Ni don't know what a good price is. I guess this one is average.

I don't think people realized the 337 was any good until about the same time MP decided to quit making them. I don't know what they sold for new "way back when", but popular used BB Mopar intakes seem to be bringing good money these days.

I feel very lucky that I was able to find one for my TF270 heads........

That was back when Zippy was still working at MP. They killed the 337 and then he talked them into bringing it back. I did some dyno tests with it for a magazine article and made really good power. They sold a few more after that and then killed it again. They really just didn't want to sell parts like that anymore no matter how good they were.

But it won't fit standard port 240 heads without head work, right?

It bolts on, but there will be a step down in port size from the intake to the head which most likely would reduce power when used with 240 heads. It is really designed for factory cast iron MW heads on a RB block. The 337 as cast tends to be a little smaller than a gasket matched MW port.
It is a good flowing intake but it does have some Mopar Performance weirdness. It has a built in valley plate which can be a good thing or a bad thing depending on which heads you are using. And it has built in bosses for a hood scoop (or maybe for EFI rails) which mostly just get in the way. It also has big bosses for either fuel injectors or for nitrous so that can be a cool feature if you're thinking of port injection down the road.

Folks can say what they want about management and they'd probably be true, but the powers that be did respond to my request to bring the part back,
and were very interested in Andy's posts and articles including that unusual intake manifold.

Afterwards, they never had tons in stock, they'd have two here and there because the demand was never there, but at least it could be ordered and you'd get it. eventually.

It was only until a regime upheaval and after those people no longer worked there that it was done away with again, because those people weren't able to babysit the part and keep it available
in spite of demand analysis' point of view that it was a waste of time. One of a million areas where OE vs Aftermarket methology does not agree and can't be reconciled.

Having bounced to two different competing OEs for about 10 years and now back to aftermarket a year ago, I feel I have an awareness of how things work and what a tangled web it can be.

Mgt was constantly chasing old stuff the enthusiast market loves, that is either on it's deathbed or demand analysis already killed off.
Meanwhile their managers are pressuring them to constantly add new stuff, usually with a tooling budget of about 25 cents.

As cast they are bigger than a 906 but smaller than a true MW, about 1/2 way in between. If I had a TF 240 port matched to a 906 on a strong high compression 440 or a stroker motor I would still run it.

Plus you could always epoxy port match it if the mis match is too much to get a good seal. Id just Epoxy it deep into the runner roof and walls (the floor should be fine) to maintain a nice gradual taper.

The 337 works really nice, I was pleasantly surprised by the throttle response...even under load....and it's even better when ported, Hood clearance is a breeze on my Low deck with the Chapman Stage VI's

Larry Smith (RIP) did this one for me well over 10 years ago.

If the O.E. is not longer interested in the product, why MUST it die? Why can't it's production be offered to the aftermarket some way or the other?

Unfortunately this rarely works because even though the OE doesn't want to make it any longer they will want a hefty royalty if someone else wants to make it. It doesn't just get released into the public domain.

It actually can, sometimes.

The very unique/almost unheard of business arrangement between Callies/Energy and Chrysler is one situation where things worked out in the other direction.
That thing cost Chrysler around a million in tooling and who knows what in manpower to create and they were perfectly content to not manage it anymore.
So: The price is jacked way up, but at least it's available. If the part is -that- good like the blocks are, then it's still worth it.

Other than literally one block casting, it's pie in the sky until someone decides to conquer it.

Someone with proper business acumen could, in fact, dig deep, determine what if any tooling still exists (most formerly at Buddy Bar in California, but could be in the landfill or scrap yard by now), and create a proposal
for licensing. They could have a licensed intake manifold product line exactly as Callies has done with blocks. If the money was right, Chrysler would probably approve it since it requires zero effort.
They would also need to manage sales, packaging, distribution, and aftersales. Callies had all that already....

It's nothing impossible, but if the idea is for the OE to just offer tooling to the aftermarket, it will never happen with Chrysler.

The alternative is make your own tooling and self finance it, more the Ritter approach as was done with Gen 3 intakes and LA race blocks, having the super obvious heavy influence of Chrysler designs but with improvements.
I'm pretty sure nobody cares if an intake has a chrysler casting number, or "M1" logo. It's neat and everything, but:whatever.
I'm pretty sure there are experienced contract designers from all over the place who could knock out improved designs without tons of effort, once the original(s) had been digitized.

Pretty sure this is much more the normal evolution of performance parts, if we are to compare a 440torker II to a street dominator to an M1sp, or a Weiand 7512 to a TM7 or torker, and so on.
The other aspects of making a part available may be too much for many to handle. Someone with the other things in place could do it.

The biggest problem with the 337 was that the matching cylinder heads were never released. The 337 is designed to work with a standard height MW head and those don't exist anymore. All of the aftermarket MW heads use a raised port.
440Source use to offer a MW version of the Stealth and those heads on an RB block would be a perfect match for the 337, but those heads are a slow seller and they might not even exist anymore. If anyone was going to sell the 337 it would be 440Source since it would work with their heads. If they bought the tooling it might make a cool combination. Basically a "factory" version of a single carb MW engine.

I think the 337 was designed to work with an aluminum version of the original MW heads. That combination would be perfect on an RB block but Mopar Performance never released an aluminum MW head that I know of. Or if they did introduce one the killed it quickly.

The built in valley tray in the 337 just adds weight and complexity when you use it with Indy -1 heads or the Edelbrock Victor heads. And I doubt that anyone really wants to spend money to develop a standard height MW head when the raised port heads work so much better. So on one hand, the analysis was correct, it was a low volume product so maybe it should've been killed. The more complex story is why was it ever created in the first place? My guess is that something went wrong. Maybe it was supposed to be part of a bigger package of parts and the bigger package didn't get approved. The cast in bosses are a clue to some future that never happened.

RPM and Stealth heads are easily opened up to MW size, if someone really wanted to use that combo.

No truer words were ever spoken.

Yeah, that is why 440Source would make a good vendor for the 337 intake (or a clone of it). That would actually be a fairly good street combo that should fit under flat hoods. 505 with MW ported Stealth heads and a 337 intake. The built in valley tray gets rid of the stamped bathtub which would be a nice touch since it looks different than most Mopar big blocks.

The performance wouldn't be as good as a Trick Flow top end, but it would be a nice street engine. Should make 600 torque and 525 power without too much problem at 10:1 CR and a 235 ish hyd roller cam.

If you want something made.....

What's the rest of the OP's combination? Maybe a different intake would make more sense anyway...

522 bottom end (10.6-1), XTQ294 cam, TF240's, QF1050AN (4150). PTC 9.5, 3.91's. 3900lb B-body. Current Holley SD

I’d say the basic combo would pick up power with the 337.
How much of a gain there would be……..only one way to know for sure.

And…….the port mismatch is probably not going to help matters.
But, it may not be the kiss of death either.
Again, you’d have to try it to know.

I’ve tested BBC rectangle port manifolds on oval port heads(which is a huge mismatch) that picked up power over their oval port counterparts.

If the manifold is priced friendly enough, just try it.
If it doesn’t do what you want……. Flip it.

The price seems decent. I'll get it. This is the one we're talking about I hope.

I haven’t had one in my shop in several years, but that looks right.

The stage 6 intakes are the same design, but are for raised port heads and are taller.

If that intake doesn't work out for you, let me know. I would be interested in it for the 500" wedge sitting in the corner. Modern ported the Eddies years ago and I think that intake would be a good fit. I would at least like to find out.

Yes, perfect intake for a set of MW ported Edelbrock heads on an RB block. You get rid of the bathtub gasket that way and the carb should be low enough to fit under a flat hood.

The 337 fits perfectly on my Stage VI Low Deck, but it has a slight 'Air gap' over the Indy Vally plate

I think Mopar Performance did a lousy job of marketing the 337 intake. I looked at it for years wondering if it would fit a 440 with MW heads. I wasn't willing to buy one to find out if that was the case. Andy finally bought one and published the results. I snagged one before they disappeared completely. Thanks to Andy for buying one and letting everyone know what it was.

I was swapping parts with a guy in Pa and he had 3 of them on a shelf along with about a dozen other BB mopar intakes.

Buy 'em up

Well it showed up today, in it's original box. I'll try it out as soon as I can.

Looks good. Be interesting to see how it fits and works for you. I had great luck with the one on my old 514. It worked much better than expected.

Like has been suggested...take a hand file, use some tape, and a vacuum 'trunk monkey' and artfully remove any down-stream interference and it'll pick the combo up for certain. Make you efforts/expense worthwhile. If it makes you feel any better you should know at Roush we'd occasionally tickle NASCAR intake manifolds ON THE DYNO to help fuel distribution. And he'd use no vacuum but blast it with shop air for clean-up. If you knew the man, you'd know he'd sell his soul for a good running engine, at that time anyway.

Comparing the ports, the are extremely close to the TF240's.

That's encouraging, at least as a starting point.

I bought a cheap(?) Harbor Freight bore scope for checking port alignment between intake and heads when installing 'em cuz you can't really see the full interface without sticking a scope way down the intake runner.

My old 337 Intake thread might have some helpful info.
https://board.moparts.org/ubbthread...mopar-337-intake-info-and-pics-here.html

How does yours go with the 337 on it?

Well, it's on. Matched up pretty good, as good as it can be. Just cleaned gaskets up some. We'll see when I get it out.

Looks great.

Can’t wait to hear the driving impressions and track results.

Wow, that looks amazing!

I'm pretty impressed with the 337, and I was running a very deeply ported Indy 440-2D MW on my 517 that I was already well satisfied with.

The big single is maybe a tick softer below 3500 but at about 4000-4200 (where my converter flashes) it pulls just as hard and then over 5500 I'd say it's a good bit stronger all the way to 6800. I never ran my 337 unported so I'm not sure how much is the manifold and how much was Larry's handiwork, but I'm guessing this manifold raised my peak torque RPM (or at least it doesn't fall off as rapidly) and I really feel it in the shift recovery to redline.

These heads flow ~335 at .500 and .360-ish at .600 on Dwayne's Bench so I think the 2D (as good as it is and out of the box can support up to 700) might have been leaving a little on the table up top. The rule of thumb for optimum power is your Manifold needs to outflow your port by at least 5-7% and the first thing you notice on the 337 is that despite the low carb height, the runners have amazing Taper (runners are larger cross sectionally at the plenum). its I think impossible to acheive taper in a dual plane configuration because the runners cant get that big to begin with.

To my understanding, port taper works kind of like a check valve, it slows the reflected pulse pressure in the runners, effectively allowing the open plenum to 'act' even Larger at WOT. Larry definitely increased the taper, i think he learned that from all the years doing NASCAR manifolds.

When I used to port Street Dominators back in the day I think that was a big part of why they improved, but it was hardly scienced-out, the SD has distribution issues between the 2-1 and 5-7 (consecutive firing) holes that are fairly easy to fix.