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W2 - Victor 2920 carb pad change - bad idea? #2675151
07/07/19 12:03 PM
07/07/19 12:03 PM
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Windsor, ON, Canada
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Diplomat360 Offline OP
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Hi Everyone!

I'm building a 408 W2 stroker, currently have the Victor W2 2920 intake and figured this should be plenty enough for my combo. This is a 90% street car, so things like hood clearance are far more important than a potential extra flow to net me a 0.10 drop in ET (just an idea to clarifly my goals). The vehicle is my 1980 Dodge Diplomat coupe, 3600 lbs 'race weight', 4k stall (behind the current 360 motor) 9" converter, 4.10 gearing. The 408 stroker is getting a Comp Cams XR292HR hydrualic roller cam but on 112 LSA, that's a 240/248 @ 0.050" setup.

OK, so the intake does have a large plenum already (for a street use I think) and since I want to run my 9800 series Carter TQ carb I really would rather avoid running an adapter due to hood clearance issues. Given the size of the carb pad on that intake it looks like it would easily allow one to shape it to accept the TQ spreadbore setup. Not sure about the impact that will have on the flow characteristics.

I am currently running the adapter on my Performer RPM intake and it works very well in that combo, but that's a much smaller intake, let alone the fact that it's a dual plane as compared to the 2920 being a single plane.

I had previously tried the Holley Strip Domintator and there was a real part-throttle difference between that and the Perfomer RPM intake, which is to be expected. Not a 'day and night' type of a difference, but you could tell there was less bottom-end/throttle response. This experience is driving me against anything that will further increase the plenum size, such as the adapter plate.

Take a look at the attached photos for what made me arrive at that conclusion.

Sooo...is the re-shape to accept a spreadbore a flat-out TERRIBLE idea?

EDELBROCK - Victor W2 - SpreadBore Template - 1.jpgEDELBROCK - Victor W2 - SpreadBore Template - 2.jpg
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2675168
07/07/19 12:46 PM
07/07/19 12:46 PM
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So. Burlington, Vt.
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I’m sure it’s been done before.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
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Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2675170
07/07/19 12:46 PM
07/07/19 12:46 PM
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68hemiss Offline
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I just saw that Shane Studley was doing just this for a S/S 360 on facebook

TQ Intake.jpg
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2675180
07/07/19 01:09 PM
07/07/19 01:09 PM
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1DGEMAN Offline
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The quick Super Stock small block guys do this all the time.


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Re: W2 - Victor 2920 carb pad change - bad idea? [Re: 1DGEMAN] #2675211
07/07/19 02:19 PM
07/07/19 02:19 PM
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madscientist Offline
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I agree. Do it. I suspect that it takes some work to blend all the runners in but I'd love to do that one day. I'm also planning to weld up the top on a SD W2 and making it a dominator top.

Pretty cool


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2675215
07/07/19 02:28 PM
07/07/19 02:28 PM
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polyspheric Offline
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How do you know where to place the carburetor? Is everyone just putting the secondaries flush to the back wall... and doesn't know if it's a mistake? What if the plenum shape and runner entries "want" the primaries even farther forward to center the total air mass? Even with the position as shown, should the runner entries be tweaked to account for higher flow to the back 4 cylinders?


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Re: W2 - Victor 2920 carb pad change - bad idea? [Re: polyspheric] #2675304
07/07/19 07:21 PM
07/07/19 07:21 PM
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Windsor, ON, Canada
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Diplomat360 Offline OP
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Originally Posted by polyspheric
How do you know where to place the carburetor? Is everyone just putting the secondaries flush to the back wall... and doesn't know if it's a mistake? ...


Good question, at least the part dealing with an ideal position. For my part I am primiarly driven by the existing mounting pad locations...so as you can see in the photos the carb studs or bolts will center the gasket and that means I would be attempting to match the shape of that gasket.

Yes, there is a bit of play there, but it's not much...however, if one was to say "move as far forward as possible", well, that would mean I probably have about 0.050" movement to the front that the current mounting will allow for and therefore I would be aiming to optimize that location.

Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2675330
07/07/19 08:41 PM
07/07/19 08:41 PM
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polyspheric Offline
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It would be nice if you could engineer in some position wiggle in case you get strange plug colors, carbon tracks, blah, but since any forward motion means having the secondaries hang PAST the edge into the pad opening...?
Obviously doing what has been done has "nothing blew up, no hasty warnings posted" so we know it will run acceptably if you just do the obvious.
But... be nice to have an advantage. That's how Garlits identified an engineer (rather than a driver or owner): someone looking to be the first/only one to get ahead of the curve.
Is there a single plane manifold originally for TQ, QJ to get a visual?


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Re: W2 - Victor 2920 carb pad change - bad idea? [Re: polyspheric] #2675363
07/07/19 09:49 PM
07/07/19 09:49 PM
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Diplomat360 Offline OP
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Originally Posted by polyspheric
...Is there a single plane manifold originally for TQ, QJ to get a visual?


Well, I'm going to contour it close in config to the non-W2 Holley Strip Dominator...but that's about where the comparisons end because I would expect the runners, the diveders, etc. to be all different. In fact, the W2 intake has runners which are nearly 0.5" taller...as far as to what actual runner volume that translates to, I have no idea. It certainly is a bigger intake.

HOLLEY - Strip Dominator Top.jpg
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2675379
07/07/19 10:40 PM
07/07/19 10:40 PM
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Maybe this will give you some ideas? Victor W2 vs. W2 Strip Dominator with a TQ spacer for comparison.




IMG_2605.JPGIMG_2613 rotated.JPGIMG_2612.JPG
Last edited by RMCHRGR; 07/07/19 10:50 PM. Reason: pics rotated

'71 Duster
'17 Ram 1500
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2675389
07/07/19 11:27 PM
07/07/19 11:27 PM
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polyspheric Offline
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From that picture looks like the pad is significantly forward, at least 1/2" of centered.
Look at the cylinders 7-8 "V" split behind the pad, vs. the 1-2 "V" ahead of it - see how much more V is showing @ 7-8?
Also looks like the side walls separating P from S slant down toward the rear.
The runner vanes are visible for cylinders 5&7 and 6&8, but underneath the roof on 1&3 and 2&4.

If this is accurate (more or less) any forward motion may help:
1. actual power
2. less chance of lean cylinder knock limiting the spark or jetting
3. save time & trouble trying out stagger (but will require tweaking any jetting already tried)
4. make plug comparos easier to read

This is not advice!! Proceed at your own risk. Good luck!
As my Dad used to say "Who dares, wins!".


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Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2676175
07/10/19 09:16 AM
07/10/19 09:16 AM
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Diplomat360 Offline OP
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Everyone...

Thanks for the awesome feedback. I dug a bit deeper into the manifold sizing information, basically the height of the carb mounting pad at the front (A measurement below) and rear (B).

Here are the details:

PERFORMER RPM (1500-6500 rpm)
======================
Part# 7176
Manifold height DESIGN: A-4.9", B-5.8", Carb pad height = 5.35" ((A+B)/2), Port exit dimensions: 1.01" x 2.17"

VICTOR W-2 (3500-8000 rpm)
===================
Part# 2920
Manifold height DESIGN: A-4.15", B-5.70", Carb pad height = 4.93" ((A+B)/2), Port exit dimensions: 1.32" x 2.00"

Soo....as it turns out (and unless the reality of the casting is way off) the W2 Victor intake is actually a lower intake (at the carb mounting pad) than the Perfomer RPM piece. Point being, I am using the adapter plate with the RPM piece right now and since the "measure twice cut once" adage readily applies here I will run the Victor intake with the adapter plate first. If that fails miserably I will then pursue the re-shaping of the pad to accept the spreadbore carb.

My biggest worry here is that the additional volume of the adapter plate will just further add to the soft bottom end, but heck, it's only 3/4" thick and a stroker motor with a 112 LSA on the cam should help this out.

Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2676257
07/10/19 01:24 PM
07/10/19 01:24 PM
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Originally Posted by Diplomat360
Everyone...

Thanks for the awesome feedback. I dug a bit deeper into the manifold sizing information, basically the height of the carb mounting pad at the front (A measurement below) and rear (B).

Here are the details:

PERFORMER RPM (1500-6500 rpm)
======================
Part# 7176
Manifold height DESIGN: A-4.9", B-5.8", Carb pad height = 5.35" ((A+B)/2), Port exit dimensions: 1.01" x 2.17"

VICTOR W-2 (3500-8000 rpm)
===================
Part# 2920
Manifold height DESIGN: A-4.15", B-5.70", Carb pad height = 4.93" ((A+B)/2), Port exit dimensions: 1.32" x 2.00"

Soo....as it turns out (and unless the reality of the casting is way off) the W2 Victor intake is actually a lower intake (at the carb mounting pad) than the Perfomer RPM piece. Point being, I am using the adapter plate with the RPM piece right now and since the "measure twice cut once" adage readily applies here I will run the Victor intake with the adapter plate first. If that fails miserably I will then pursue the re-shaping of the pad to accept the spreadbore carb.

My biggest worry here is that the additional volume of the adapter plate will just further add to the soft bottom end, but heck, it's only 3/4" thick and a stroker motor with a 112 LSA on the cam should help this out.



As a general rule, plenum volume increases help with bottom end power.

Also, if you shape the Victor to the adapter it will work much better. If you just bolt on that adapter the exit losses will best big it will most likely kill power.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: madscientist] #2676294
07/10/19 02:41 PM
07/10/19 02:41 PM
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polyspheric Offline
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Mixture is really stupid, and always trips over a surface interruption - which reduces mass flow.
And also raises a more difficult question: "after it trips, which way will it go?"


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Re: W2 - Victor 2920 carb pad change - bad idea? [Re: madscientist] #2676389
07/10/19 08:30 PM
07/10/19 08:30 PM
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Diplomat360 Offline OP
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Originally Posted by madscientist

As a general rule, plenum volume increases help with bottom end power.

Also, if you shape the Victor to the adapter it will work much better. If you just bolt on that adapter the exit losses will best big it will most likely kill power.

Ohhh???

So maybe I'm just confusing the soft "bottom end" idea with slow/lazy part-throttle response due to the combination of single plane and large plenum?

Quite honestly all I have read has always suggested that you do not want an intake with a large plenum on a street vehicle, now maybe this was always part & parcel of a single plane intake and therefore the unfortunate link?

Anyways, OK, good to know this. Regarding the adapter plate, yes absolutely. I am intending to match them, in fact even my Perfomer RPM intake is matched, and that is despite the fact that there is that gaping divider wall on a dual plane. In my case I had actually ground down the wall by about 0.5" and rounded the leading edge, all in hopes of making this air barrier as unobtrusive as possible.

Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2676415
07/10/19 09:55 PM
07/10/19 09:55 PM
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Why are you wanting to use a camshaft with 112 LSA on a SB confused shruggy
If you don't have that cam now don't do that tsk twocents


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Diplomat360] #2676420
07/10/19 09:59 PM
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Originally Posted by Diplomat360
Originally Posted by madscientist

As a general rule, plenum volume increases help with bottom end power.

Also, if you shape the Victor to the adapter it will work much better. If you just bolt on that adapter the exit losses will best big it will most likely kill power.

Ohhh???

So maybe I'm just confusing the soft "bottom end" idea with slow/lazy part-throttle response due to the combination of single plane and large plenum?

Quite honestly all I have read has always suggested that you do not want an intake with a large plenum on a street vehicle, now maybe this was always part & parcel of a single plane intake and therefore the unfortunate link?

Anyways, OK, good to know this. Regarding the adapter plate, yes absolutely. I am intending to match them, in fact even my Perfomer RPM intake is matched, and that is despite the fact that there is that gaping divider wall on a dual plane. In my case I had actually ground down the wall by about 0.5" and rounded the leading edge, all in hopes of making this air barrier as unobtrusive as possible.




Soft bottom end is usually a converter/gear issue. You could have other issues as well. I've never experienced "soft bottom end" and I haven't ran a dual plane intake on purpose ever. Taken many off, but never start out with one.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Cab_Burge] #2676421
07/10/19 10:00 PM
07/10/19 10:00 PM
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Originally Posted by Cab_Burge
Why are you wanting to use a camshaft with 112 LSA on a SB confused shruggy
If you don't have that cam now don't do that tsk twocents



Forgot to mention cab nailed this. That wide LSA is a killer on stuff with stock type heads.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: madscientist] #2676422
07/10/19 10:02 PM
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Ok, had to go back and read your OP. I don't know how any 408 with a 4.10 gear can be soft on the bottom. Define what you mean. I'm lost. Someday I hope to drive a car with soft bottom end so I can actually see what it is.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: W2 - Victor 2920 carb pad change - bad idea? [Re: Cab_Burge] #2676426
07/10/19 10:26 PM
07/10/19 10:26 PM
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Originally Posted by Cab_Burge
Why are you wanting to use a camshaft with 112 LSA on a SB confused shruggy
If you don't have that cam now don't do that tsk twocents


Cab_Burge,
Yeah, already have the cam, picked it up 2nd hand (super cheap, custom grind due to the LSA and never used) ...and that is about the entry-point size I was aiming for with the hydraulic roller setup (which is my 1st time into the roller domain). So all in all I thought: "heck, why not, worthwhile trying it out". If I was buying brand new I would probably do a 110LSA (which is the actual LSA on the regular CompCams XR292HR grind). This being just 2 extra degrees I thought it shouldn't be all that bad...

The hydraulic flat tappet I have now (Hughes HE3844AL) is a 238/244 @0.050" on 108LSA. Given the amount of time the car spends on the street I thought I would go back to the 112 LSA. Prior to the Hughes grind I was running a Crower #31243, which is their 282-HDP Compu-Pro grind, 228/238 @ 0.050 on 112LSA.

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