Dual quad 440 jetting starting point

[hoover]

Does anybody here have a good starting point for primary/ secondary jets and metering rods for a pair of edelbrock 1405's?

 

[gtxrt]

Does anybody here have a good starting point for primary/ secondary jets and metering rods for a pair of edelbrock 1405'

98 primary and 86 secondary with stock 1405 70x47 metering rods

 

[hoover]

Thanks!

 

[lewtot184]

I use .101primary an d secondary with 70x47 rods and orange springs with a ch28 intake. Engine has some cam (nothing radical), edelbrock heads and headers. Ignition is dailed in for the combo. Works very well!

 

[gtxrt]

2x4 ch28 intake

 

[junior340]

I happened to be going through my Dual set-up right now so good timing on this thread. I use a Weiand with a couple Comp 500s. It always has run a little fat.

 

[gtxrt]

stock primary are 100 jets and stock secondary are 95 jets

 

[4speed68rt]

Start with the stock jets & rods that it came with and go from there. You have to use the tuning manual for the Edelbrock that you have to get the correct combination of rods and jets to get desired percentage of lean. The stock setting is "good" for sea level. The higher the altitude, the leaner you need to be. Doesn't really have to do with engine size, but with optimum mixture of fuel and air,(AFR).

 

[gtxrt]

Start with the stock jets & rods that it came with and go from there. You have to use the tuning manual for the Edelbrock that you have to get the correct combination of rods and jets to get desired percentage of lean. The stock setting is "good" for sea level. The higher the altitude, the leaner you need to be. Doesn't really have to do with engine size, but with optimum mixture of fuel and air,(AFR).

why would you start with stock jets in the 1405 carbs when you buy the ch28 intake Edelbrock sends you the right jets to start with. maybe you didn't see post 5#. then you could go from there up or down.

 

[gtxrt]

I happened to be going through my Dual set-up right now so good timing on this thread. I use a Weiand with a couple Comp 500s. It always has run a little fat.

the 500 cfm will kill performance I tried them and went back to the 600 cfm.

 

[4speed68rt]

why would you start with stock jets in the 1405 carbs when you buy the ch28 intake Edelbrock sends you the right jets to start with. maybe you didn't see post 5#. then you could go from there up or down.

I guess that I missed that. I guess that I assumed that the OP got the intake at a swap meet or something like that. My point was to go with what the engineers at Edelbrock say, don't just guess, or go with what somebody else did, in some other location. Thanks

 

[lewtot184]

I use .101primary an d secondary with 70x47 rods and orange springs with a ch28 intake. Engine has some cam (nothing radical), edelbrock heads and headers. Ignition is dailed in for the combo. Works very well!

View attachment 1677058

9

2x4 ch28 intake

View attachment 1677080

Is that from the Don dulmage booklet?

 

[lewtot184]

When I started with this system I had a 1406 primary and 1405 secondary. Anyhow I felt the carbs were a mismatch and jumped thru some hoops to get the clusters all squared up. I did do the lean primary thing and eventually had to keep jetting up. It would drive ok in town but would run rough and erratic after some highway time. Anyhow, I gradually made adjustments to improve all around driving and currently it runs sweeter than a bowl of peach cobbler. I also went after the idle jets. 1405 was .028 and the 1406 was .032 out of the box. Both carbs .035 now and that smoothed the low speed operation out nicely.

Next step is pair of 1407's hanging on the wall.

 

[gtxrt]

9
Is that from the Don dulmage booklet?

These are the instructions that came with ch28 intake when I bought it new from edelbrock many years ago. they sent the jets with the intake.

 

[lewtot184]

These are the instructions that came with ch28 intake when I bought it new from edelbrock many years ago. they sent the jets with the intake.

Ok. I didn’t have that info. I really think from experience that the OOTB 1405 jetting is a very good starting point.

 

[gtxrt]

mine runs best with 89 secondary jets and 73x47 rods with the 98 primary jets that help keep the plugs clean at cruising speed. I am sure every engine is different.

 

[khryslerkid]

Does anybody run progressive linkage? I had a very lean condition on the front four cylinders using this setup. Front cylinders were running way too hot. Went to a one to one and all is fine. I did fatten up the jetting a little also. Using a factory 2x4 cast iron manifold and two 1405s with a mechanical choke on the rear.

Biggest thing to check on these edelbrock carbs is the float level. They are all over the place from the factory. Also if there is a blue accelerator pump installed replace it with the orange one. Ethanol will destroy the blue one in no time.

Here's the different factory jetting between the 1405 and 1406, and springs

1405 metering jets pri .100 Sec .095

1406 metering jets pri .098 Sec .095

Metering rods 1405 .070 X .047

Metering rods 1406 .075 X .047

Step up springs 1405 orange

Step up springs 1406 yellow.

 

[lewtot184]

I've always used progressive linkage. When I got into this I wanted something close to street hemi set up. The 1405 is the same size but internally different. Anyhow, the old 409 and street hemis were progressive. Mine burns very clean. Doesn't seem to have any distribution issues.

 

[khryslerkid]

I've always used progressive linkage. When I got into this I wanted something close to street hemi set up. The 1405 is the same size but internally different. Anyhow, the old 409 and street hemis were progressive. Mine burns very clean. Doesn't seem to have any distribution issues.

I've always been curious how the factory did the progressive. I tried different things but couldn't get rid of the lean front cylinders. While idling, using a IR gun, they were way hot like 650, 700 degrees and the back four were 600 or less. Maybe it's the manifold but it's an original factory one used on the 413.

 

[lewtot184]

I've always been curious how the factory did the progressive. I tried different things but couldn't get rid of the lean front cylinders. While idling, using a IR gun, they were way hot like 650, 700 degrees and the back four were 600 or less. Maybe it's the manifold but it's an original factory one used on the 413.

You may want to play with the idle jets on the front carb. 1406 has about .005" larger idle jet.