289 weber intake question

#1
I want to put four 44 idf webers on my 293 build. I have noticed that there are two different styles of intake for quad webers. One has a single coolant outlet that looks like it would house a thermostat and the other has two outlets. Im not sure what is the right intake for a gt40.
 

Active Member
#4
As I understand it, the twin outlet manifold is run without a thermostat. Anyone care to chip in with more info?
 
#5
are the "Cobra" and "FAV" manifolds different? something about the way the carbies face?

also keen to learn how the two manifolds control temperature.
 

Active Member
#7
One other point of difference is that Weber orientation is different on the twin outlet manifolds vs most single outlet ones. i.e. fuel line is on outside for both banks on single outlet manifold while fuel lines are on outside for one bank and inside for the other with twin outlet manifolds.
 
#8
That is interesting information. Thanks for the pics too! I noticed most intakes are designed for 48 ida carbs will 44 idf carbs bolt to the manifold without modification?
 

Jac Mac

Active Member
#10
The manifolds with carb fuel inlets both facing outboard favour the idle and part throttle mixture being biased to the upper part of the port runner, whereas the manifold with all carbs facing left or right will have one bank bias the flow to bottom of intake runner and other bank to top. Two outlets seem to work better for race applications, for cars n coffee applications it probably wont matter to much and most of those guys are more concerned about heater operation along with A/C.
 
#11
Gents

The IDA vs IDF fitting is quite different

I have attached a couple of pictures for your reference

IDAs have 120mm centres where IDFs are 90mm so no they don't fit on an IDA manaifold

For the average guy IDFs are less fussy to look after in particular with regard to accelerator pump as they use a diaphram which is less likely to give trouble than the IDA piston system.

In either case good filters and good fuel solve those problems.

For personal preference go for an intake with built in thermostat housing unless you have enough gear to build all that.

Regards

KB
 

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#13
A remote thermostat housing could be built and put in place where the two outlet lines merge into on pipe. I wouldn't think that would be too difficult to fabricate.
 

Jac Mac

Active Member
#14
If I run IDAs would 48s be too big for my 289? It will be a very mild 289 only bored 30 over with a mild cam and aluminum heads.
48mm is the dia of throttle butterfly, you can fit any size chokes/venturis you desire....Your Alloy heads will likely flow as good if not better than the ported 289 heads back in 1966.
 
#17
Doc what is the little pipe that connects to the top of the two main outlet pipes? Also what is the extra outlet above and to the right of the main collector? Excuse me if I am wording all of these parts poorly, I have zero experience with this type of cooling system.
 
#18
how much of the front of the manifold can you actually see in the engine bay once its all buttoned up? especially with a turkey pan on it.

I was trying to find a good photo but i'm struggling at the moment.
 

Randy V

Administrator
#19
how much of the front of the manifold can you actually see in the engine bay once its all buttoned up? especially with a turkey pan on it.

I was trying to find a good photo but i'm struggling at the moment.
I agree...
You see very little and what you do see, it is a struggle... Frankly, I feel its one of those components of originality that can be overlooked for more modern convenience and packaging of an integral thermostat and a single hose. It will change nothing in terms of performance or efficiency to run dual hoses.
 
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