Mopar 337 intake

Anyone remember the member that had one for sale a while back?

Jegs: $262.99 http://www.jegs.com/i/Mopar+Performance/312/P4876337/10002/-1
Summit: $272.97 http://www.summitracing.com/parts/dcc-4876337/overview/

Not in stock either place.

I had one I thought about selling....then I thought better and had it ported. Works awesome BTW on Chapman CNC max wedge heads.

Contact Todd @ Marsh Racing

Nice Streetwize!

Wise.......... I'm guessing you now prefer it to the 440-2D?

When I ran one on a street/strip 572 I was as skeptical as anyone about how it would work, but it worked surprisingly well on that motor.

Fast,

Yeah the ported 337 works awesome with the Chap CNC Max Wedges on the 517 as you know i really liked the ported 2D but if anything the 337 is even better. The throttle response is even quicker than before. Revs like a comp eliminator motor...I'm impressed.

That looks good Wize. One of these days I hope to try the 337 on my 63. Ron

Wise, Where did you send the manifold to have it ported ?

I was pretty sure if you tried one you'd be a believer.

I think we tried to tell you that for a long time!

I did a lot of testing with the 337 intake a few years back and was shocked at how much power it made for me. It doesn't look like it would make much power since it is fairly low profile. But for some reason it really works. The porting on yours looks really nice. I always ran it as cast, I bet a ported verson would really work well.

Just to be clear...

I really had no doubt the 337 would be a very good intake, both Andy and Dwayne's dyno testing proved that to me)...it's just that my particular 440 2D has a lot of porting and ( correct me if I'm wrong) everybody who tested their 2D's againt a 337 never had the level of deep porting this one did, and even on 572" motors ( Old Hippie and Firefighter both have 572's) the advantage of the ootb 337 vs the ootb 2d was clear to see ....but not really 'eye popping' dramatic, especially considering the heads and short blocks they were compared on. You all tested 2Ds, just not THIS 2D.

To put it another way I assumed the ootb 337 superiority would be even less dramatic ( if at all) against MY Ported 2D....thats really all I was saying because I ran the 2D with both the as delivered MW ports and ported even deeper than the Dr Air article intake. Before I ported it you could feel the ootb 2D was holding my 517 back by around 4500-5000, but ported that went away and she would pull hard all the way to 6800. I suppose the dual plane cross section hits a choke point as cast and the deep porting helped, I had to go up 3 jet sizes as result of the porting I did.

When I learned that my good friend Hollis Page (HPEngines on Moparts) had teamed up with 30+ year veteran NASCAR porter and engine builder Larry Smith, well, it was pretty much a slam dunk. I had the 337 for several years and I gambled that if I ported it it might be worth changing out the 2d for it, turned out to be the right choice. I supposed as much as I ported the 2d, this motor still wanted a bit more.

So to be fair, I never tested my ported 2D against the as cast 337 ( I wanted to do a back to back chassis dyno test but my gut was it would be a wash - A few less lb/ft but maybe a few more hp up top. Didn't seem worth going after to me. Add to that the motors tested probably (by the bench flows quoted) weren't quite as high flowing at .300-.600 as my Chapmans, so the torque/hp trade off might have even been less dramatic on my motor, not below 5000 or so anyway.

You can probably tell from the pics my 337 has been worked masterfully... And (ported to ported) there certainly is an improvement over what was already a pretty stout manifold. What suprises me is I never would have believed the ( already very good) throttle response and off idle roll-on would be better with a single plane over a pretty healthy dual plane.

Turns out the manifold and heads (and Fast knows these very heads hands-on) seem very well suited to one another.

I have a vintage Holley Pro dominator W2 tunnel ram I'd love to let Larry work on next! I figure I have close to Indy race intake flow...that (as Andy points out) fits under a stock hood and has better street rpm velocity for better roll-on torque and drivability.

Just in case anyone else is interested in one of these I got one from Mopar performance for $224.00.

Good deal. That is a great price for that intake. Glad that MP still has some in stock.

Is the 337 a 4500 carb intake, or 4150? Any idea how much lower the 337 is than a super Victor? How much hood clearance would be gained with the 337 v the sv, and is the performance level similar?

The 337 is a 4150 flange, and is a very low profile. I wrote down the height difference in my notes, i would have to dig them up to see the exact difference(iirc it was close to 2 inches lower at the carb flange than my M1). I ran it for a short time and wasn't impressed, but after reading some of these responses about it in this thread, I'm wondering why I lost ET compared to my M1 ? maybe it's my combo ? my engine didnt seem to pull as hard thru upper rpm with the 337 compared to the M1. I lost a few mph with the 337.
https://scontent-iad3-1.xx.fbcdn.net/hph...110097384_o.jpg

standard or m/w ports?

both intakes are standard port as are my heads.

The 337 is a 4150 flange and it is a lot lower than a Super Victor. There are some old threads on here that cover the intake. I did a lot of dyno testing on that intake a few years back. The 337 has MW ports and a built in valley cover so it is the only single 4bbl intake that fits original MW heads on a RB block.

Here is an engine article I wrote that covers the 337 v. SV testing: http://www.hotrod.com/how-to/engine/mopp-1206-project-505-the-final-chapter/

That's interesting, because the MP online cantalog shows the P4876337, P4876128 & P4876129 intakes as all being max wedge ports. With the 337 being for 4150 carb, max wedge, and stock heads. The 129 being for 4500 carb, max wedge stage VI heads. And the 128 being for "four barrel carb", max wedge stage VI heads.
Not sure is that "four barrel carb" on the 128 means it will handle both 4150 and 4500.

I'm looking for a lower profile 4500 alternative to the super Victor on the Eddie super victor max wedge heads.

Interestingly the 337 is considered a max wedge, but as delivered the ports are really only slightly larger than 1/2 way between a 906 and a true 2.6" x 1.3" Max Wedge. They may have done this intentionally in the height to allow it to be used on a well ported 906 size window.

One great feature of the 337 for high end horsepower is even as cast it has very nice taper and cross section transition from the plenum to the port mating flange. This is good for power up high ( keeping the plenum charged) but i could see on a 440-470" motor its going to take more rpm to get it to the sweet spot, so with a big cam it's going to be more of a 'light switch' torque curve. On my 11.5:1 517 it seems nearly perfectly matched.

You might be able to rework the plenum with a 4500 bolt pattern and then it would be a lower profile alternative to the Super Victor. When you add a 4150 to 4500 adapter on top of the 337 it gets about as tall as a Super Victor.

I stand corrected, the 337 is advertised as having max wedge port..but I'm not sure how close it is to actually max wedge port size. My standard port MP aluminum 452's are not max wedge and I'm certain there was very little difference in the port size from the intake t
o the cylinder head. I'm also certain I didn't use max wedge gaskets.

You most likely had some port mismatch with the intake ports larger than the heads. That might be why you didn't seem much performance improvement. The ports in the 337 are larger than std ports although they usually are smaller than a full MW port. I've run the as cast 337 intake at 800 hp so the ports are big enough to work at that level.

As I mentioned above, the 337 is not as tall nor nearly as wide as the true MW window. I think they did this on purpose so a well ported 906 size port could consider it as an option.

Before sending my manifold to Larry I scribed the port match to my heads and gaskets, there was a good bit of width and some roof height grinding to get it there.

I went back and saw some dyno sheets from a 572" 4.5 x 4.5 (I'm sorry can't remember whether it was Firefighters or Old Schools but compared side by side their 2d vs the 337 each with a 1" open spacer the peak results were pretty 'close' 713.9 @ 4600 to 721.2 @ 4500 on torque and 697.3 @ 5700 to 705.2 @ 5800 on HP, my motor is "only" 517 and the 2D I had was deeper ported, so you can probably see why I wasn't in any real hurry to swap. the 337 was more, just not that much more. I also think (to make it true "apples to apples" fair fight) the 2D could have been tested with a larger carb (the 337 had 1050/4150 and the 2d only had an 850/4150?). If anything a dual plane generally wants MORE CFM to compensate for the divided plenum, a single plane (as we all know) allows each port to access all four barrels of the carb. I've been running a 1000cfm/4150 Pro systems on mine with both manifolds.

I have a 337 intake on MW ported Performers. I use a 1050 Dominator on an adapter and it works great. As delivered the ports are right in between std and MW. Having the built in valley tray is a huge plus. I've always been surprised this intake hasn't caught on more than it has.