Factory dual manifolds

[41/53dodges]

Good morning flathead truck gang!

 

Looking for some insight on the factory dual manifolds, particularly the carbs.

 

I picked up a set that was missing one of the E9Y1/E9K1 carbs a few years ago, been watching the usual sources for another but no luck so far.

 

I've got a pile of ETT1's laying around, I believe the bore & venturi size are the same and jets are different.

 

Can anyone confirm that's the case, and does anyone have any leads om the correct jets?

 

Thanks guys,

 

Josh

[greg g]

Here is some thing to consider.  When you add a second carb you essentially half the air flow passing through each carb.  Since it's a proportional thing, your are going to suck less fuel out of each main jet.  So the normal reaction would be you need larger jets, but I think the opposite is true and the jets need to be smaller.  Then again, I may be down the wrong rabbit hole.  If they will bolt on, and venturi and throttle plates are the same size, I would bolt them up and see how it reacts.  Does this set up have seperate manifolds with a balance tube or is it a single casting with two inlets.  Second point the factory setup had dual exhaust also.  What are your plans there?  I am running a 230 with dual Carters on a Fenton intake.  It runs single exhaust through 2 inch I'd pipe with a dynoflow shorty turbo muffler.

[41/53dodges]

I believe the jets are indeed smaller, I don't recall what the exact size of the ETT1 was but I recall it being larger than the factory dual E9K1's

I've got the full factory system from a 2-1/2 ton truck, sans the one missing (destroyed) carburetor.

Haven't decided what I'm doing with it for exhaust, that'll definitely require some playing so it doesn't sounds like a rental car

 

But, perhaps you're right. I'll throw on a pair of ETT1's and see what I get out of it, because worst I get is running crappy!

[greg g]

Looks like Governors under the carbs.  We're they to limit top rpm or smooth reaction to load conditions?   I remember my cousin driving a beer delivery truck.  He hated his route because he delivered in a city 15 miles from the terminal. And the truck, a late 50s Gas Intrenational would not go over 42 mph.

[Dodgeb4ya]

Dodge used the governors as rpm limiters.

As for the E9K1 carbs they are slightly larger flow carb than the ETT1.

Main jet for the E9K1...334 CC

Main jet for the older ETT1...312-316 CC per minute.

The accelerator pump discharge jet is a bit bigger on the ETT1 than the E9K1.

E7T2 is a direct newer replacement for theETT1.

All three of these carbs are close in spec.

[47 1.5 ton]

 I have a pair of ETT1’s on the factory manifold (without the governors) and opened the main jets up.005”. If I take the carbs off again will go another .002-003” as they run a little lean with todays fuel. Biggest issue I had was getting those balanced coming off idle as the carbs want to switch the lead (dominant)for a second which I believe is due to the balance tube on top of the manifold. Can be seen with (2) vacuum gauges when Hooked to each carb. I have more accurate readings now once I replaced all the linkage and rod ends with modern eye (Heim) type ends.

 Kevin

Edited December 20, 2023 by 47 1.5 ton