logo
12 Port News - Features
12 Port History
Casting Numbers
Online Store
Tech Tips
Become a Member
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Aug 2012
Posts: 166
S
stan z. Offline OP
Contributor
OP Offline
Contributor
S
Joined: Aug 2012
Posts: 166
Hey guys! I'm in the process of gathering up parts and pieces for my 250. I'm looking to build a hoped up street motor for my 46 Chevy pickem up. I want to build something that not only sounds and runs good but is an eye catcher under the hood.

I was looking at the Clifford dual and side draft intakes. What kind of issues will I have with hooking up the TV cable from my 700r4 to these intakes. The dual Weber setup looks pretty much the same as any Holley hook up. Can the TV cable even be hooked up to his side draft unit? Figured I would ask hear first before trying to call and just getting a busy signal. Thanx guys
Heres a pic of my ride, hope this works!

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
Those are 2 very different set-ups. The dual Weber is a normal street carburetor with progressive secondary linkage and a high vacuum cruising circuit.
The side draft DCOE has neither of these.

Joined: Aug 2012
Posts: 166
S
stan z. Offline OP
Contributor
OP Offline
Contributor
S
Joined: Aug 2012
Posts: 166
 Originally Posted By: panic
Those are 2 very different set-ups. The dual Weber is a normal street carburetor with progressive secondary linkage and a high vacuum cruising circuit.
The side draft DCOE has neither of these.


Yeah, I understand the 2 intakes are of totally different concepts of fuel and air delivery. I was more curious as to whether the side draft was even compatible with a 700 r4 and if its really street worthy. I was just looking for something a little different as far as an intake goes but would still be user friendly. The dual Webers look as if they are a pretty straight forward install. I was just curious if there was an aftermarket bracket that would work for the TV cable from my trans.

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
Many failures have been posted based on just bolting something up. The instructions are pretty complicated, not straight-forward at all.
I don't know of any carb linkage that is designed for this except for Holley 4 bbl.

Joined: May 2011
Posts: 378
7
Contributor
****
Offline
Contributor
****
7
Joined: May 2011
Posts: 378
I pretty much believe in "there are no bolt-on parts". You cannot just slap a set of different carbs (or other parts) on an engine and assume it would work right. In fact it is almost guaranteed to do the opposite. You would need to know how each carb model and application works, what jet and emulsion tube etc. does what, to be able to tune it to your engine's needs in every situation. This means replacing a bunch of parts to find the right combination. You would need to have access to these parts in various different sizes. Plus you would need to be able to verify the results reliably, forget "tune by ear". For most street applications and an experienced tuner, a regular narrow band O2 sensor would suffice. If you can't get it in the ballpark from the start, you need a wideband setup. (more expensive, but more forgiving as it offers a wider range of data values as the name implies).

This in mind... armed with experience and spare parts, you should be able to make any carb work. Or any multiples of them.

The progressive dual weber is a common "replacement" carb, geared towards smooth progression and driveability, as well as economy. When used to replace a single throat carb, it usually offers more power due to the additional second throat flow.
But it is not a performance carburator. These were factory carbs on many older cars. Think "4 cylinder Ford Pinto" and you get the idea. They are less "tuneable".

The DCOE series is a performance carb, which while FULLY streetable and smooth to drive when tuned right, allows for more power potential. It generally is used in applications where you have dedicated, individual intake runners, one carb venturi for each intake valve. You can tune the mixture for each individual cylinder. They have also been used in shared venturi applications, but they aren't optimal for plenum intakes.

The Progressive Weber is designed for setups where there is a shared plenum space immediately under the intake, a "mixing bowl" where all mixture is first dumped, and each cylinder then draws from that general mess of fuel and air. The said plenum needs to be HOT, to keep the mixture alive and prevent fuel from falling out of suspension and creating droplets of raw fuel, which won't burn. This plenum design results in less accurate mixture control for individual cylinders, but works fairly well when everything is well matched. Sadly, by having to heat the mixture, you lose some power potential. From a performance standpoint, you want the ingoing mixture (air) to be as cool as possible.
Since the progressive webers have fewer parts that are replaceable or adjustable, they are basically simpler to tune. AND would work reasonably well in our plenum-type intake configurations.

Joined: Jan 2005
Posts: 2,123
Likes: 3
P
1000 Post Club
**
Offline
1000 Post Club
**
P
Joined: Jan 2005
Posts: 2,123
Likes: 3
This is fascinating.

Joined: May 2000
Posts: 1,464
1000 Post Club
*****
Offline
1000 Post Club
*****
Joined: May 2000
Posts: 1,464
Nice truck BTW.


FORD 300 inline six - THE BEST KEPT SECRET IN DRAG RACING!
Joined: Jan 2010
Posts: 493
P
Contributor
****
Offline
Contributor
****
P
Joined: Jan 2010
Posts: 493
 Quote:
...factory carbs on many older cars. Think "4 cylinder Ford Pinto" and you get the idea


"older"? What is '52 rochester model "B"? "oldernhell" perhaps.

By 1972 these Pinto carbs were deep into the emmisions era when reduced engine timing,compression,and excessive leaness required everything from heated air cleaners, 195 degree thermostats, looser factory torque converters to instill any thing near the driveability of the presmog era into this era's vehicles. It was'nt until 1975 when the catalytic converters appeared did we see any appreciable driveability improvements.
Any factory carb is "less tunable" because they were specifically designated for a specific make/model. This is why Hollys enjoy the hotrodder's praise-they are "fit-alls" and have to meet no one's emissions tests, they are a bit primitive and can be resonably tuned or adjusted to suit individual tastes. The same Holly will not perform admirably from Pikes Peak to Death Valley as most factory carbs will on their original mounts.

Joined: Jun 2012
Posts: 12
R
Active BB Member
Offline
Active BB Member
R
Joined: Jun 2012
Posts: 12
Those dual webers seem to work fine on 240Zs
anyone have a pic of a manifold to mount 2 to a 250?

Joined: Apr 2006
Posts: 534
D
Major Contributor
Offline
Major Contributor
D
Joined: Apr 2006
Posts: 534
70Nova: 5200 Weber doesnt need to be THAT hot. My Pinto ran a 160F tstat & did just fine. I even ran an open air cleaner all of the year - in Michigan, though it WOULD ice up in 30F-40F moist weather.

Preacher - dunno when/if emissions ruined the little Weber 2v 5200 but 1972s ran good. My 72 Pinto was the bane of every BMW and 914 it met back around 1980 (ok big cam & headers). Jets&AirBleeds easy to swap (in fact, I did take it from MtEvansSummit to DeathValley w/just and air bleed change). Good carbs, I keep meaning to try em on our Chev 6 but SO many carbs to test already!

Joined: May 2011
Posts: 378
7
Contributor
****
Offline
Contributor
****
7
Joined: May 2011
Posts: 378
It's not the carb itself that needs to be hot, it's the intake. The carb needs to stay cool, hence the thermal isolator/spacer between it and the manifold. Once the mixture leaves the carb, the fuel mist will want to fall out of suspension and form droplets on the intake manifold walls. Droplets don't burn, only fine mist will. The hot manifold reduces the droplet problem and helps vaporizing the fuel before it enters the combustion chamber.
Not the best terms to use here perhaps, but forgive me, it's my 3rd language ;\)

If the intake and venturi velocity is high, the mixture quality/atomization is better and you can get away with a cooler intake manifold. Ours, as I have come to understand, suffer from poor, slow flow by design, and that's why they came up with the lumps, to redirect and speed up the intake charge. Someone correct me if I'm wrong.

Joined: Jan 2010
Posts: 493
P
Contributor
****
Offline
Contributor
****
P
Joined: Jan 2010
Posts: 493
its nice to luck out once in a while, good deal! Those short intake runners are easier to keep warm too.


Moderated by  stock49, Twisted6, will6er 

Link Copied to Clipboard
Who's Online Now
1 members (41 Coupe), 107 guests, and 59 robots.
Key: Admin, Global Mod, Mod
Newest Members
Ryan Clark, chevy454, TCH54, beansprout01, GH60
6,777 Registered Users
Sponsored Advertisement
Sponsored Advertisement
This Space is Available
Powered by UBB.threads™ PHP Forum Software 7.7.5