Eldebrock Carbs

[rebelrouser]

I just found a 1405 and a 1406 for $200 shipped. They haven't been off the car very long and from what I found the kits are cheap. Since I know nothing about eddys what do you all recommend buying for tuning purposes? I've got a ton of stuff for holleys, nothing for these though.

Back on topic.

I have ran the Tall tunnel-rams on my sbc 350 engines on the street for decades.
The small original carter afb carbs are down on power vs the 625 AFB or 600 edelbrock # 1405.
They just do not rev in the upper RPM area well.

I bet money it is not the CFM but the entry shape of the booster.. it is much more flat than the larger carbs.. almost like you put a brick in the flow path.

I would get 18 MPG with 2 600's just as good at the MPG game as a single carb.
I tested on a 357" sbc a much modified 4779 on an edelbrock RPM intake vs the tunnel-ram and out of the box edelbrocks 1405 carbs and the edelbrocks made 53 minimum HP at the wheels everywhere. The dyno operator asked if anything else was changed I said yes I pulled the HEI and am running an out of the bo single point distributor with a Ford coil.

Idle and part throttle cruise AFR was mid 14's and wide open was in the 12.5 range.

When I began running the edelbrock 600's years ago the jetting and rods did not make much seat of the pants difference in the tall tunnel-ram.

I say get the 600 edelbrocks and stick them on and run them.
Recently pulled an 800 cfm and strip dominator intake off buddies 11.0 compression 396 BBC and stuck on a tall ram with 2 1405 Edelbrocks and he said it never made that much power his hands were shaking after the first drive and you could not smack the grin off his face.

Very good carbs and you do not need annular boosters.

One mod that really helps in those carbs is to get the step up springs correct.
My engines pull 11" or more vacuum at idle and the stiffest spring is not stiff enough for my taste.
Kind of like running a 6.5 power valve vs a 9.5. You can't get a factory edelbrock spring to step up at 9" but add an ink pen spring into the stock spring and you can.

But run them as is If you have 5" idle vacuum you will want a softer spring though.

I have used cheap ink pen springs. I fire it up let idle, take the caps off and play with the throttle and watch a vacuum gauge to see exactly when the piston moves. Then start stretching the spring until I get it at the opening point I want. Of course last guy I told to do this, racked the throttle and the piston shot up in the air, ands the engine almost swallowed it. You got to hold your hand close to catch it. and only do one side at a time.

[jeff swisher]

On the edelbrock performer series like the 1407 and 1405 etc you can loosen the screws holding the cover over the piston and rotate it a bit and snug the screw and watch the power piston action without parts jumping out. I think the AVS has a wall in the way.

I have used the ink pen springs way before edelbrock ever put their name on these carbs.
I do have many old AFB's from the 1960's and they had very stiff springs in them and most metering rods had a small step from cruise to power.
like 65-55.
I have one small one that is an AFB but has no secondary air valve and not machined for one either.

[quickd100]

The early afb carbs didn't have one. I've got a set of 59' 383/413 carbs no velocity valves. I tried them on a 2x4 manifold a couple times worked great with a 4 spd not as well with an auto.

[Steve K]

I thought vacuum is what keeps the metering rods down and in a low vacuum engine you need the lightest shortest spring to keep the rods down. My engines run maybe 6-8 inches vacuum hot at idle and I’ve been running the spring set up as described above. Have I got this wrong? Don’t understand why one would put a second spring (pen) inside the step up springs. In my mind this would work opposite to what is needed on a low vacuum engine. Or maybe I’m totally misunderstanding this in which case I’ll blame it on dementia.

[F-BIRD'88]

Again if you want to switch up the holley 1850's for 2xEdelbrock carbs for your street tunnel ram, I highly recomend the 650 AVS2 carbs for you.
You will benefit from the annular style primary boster and also benefit from the user friendly adjustable AVS style secondary air doors on these VS the afb style 500 cfm edy carbs.

One thing that is CRITICAL to these carbs (as well as your current holley carbs) is correct paper element fuel filters and AVOIDING excessive un-nessessary high fuel pressure. 5 to 5.5 psi fuel pressure is all you want.
More just greatly increases the likelyhood of carb flooding (even on your holleys)
The 1850 holleys are not set up nor calibated for dual carb nor tunnel ram use. The vac sec setup on these also as is is not well suited without mods for this.

You will need the tuning kits specific to the 1905 650 AVS2 carbs as a start point and may need some other specific jets and rods for the final tune.
Do not attempt to tune blind with either the edys or your holleys. .. Get a afr gauge. Chassis dyno time is great.
I bet the diz setup can use work too.

Ya the 2x 1850 holleys inline are annoying when they flood and when swapping jets and setting up float height
.

You will find the eddy carbs much more street car friendly on a street tunnel ram car, especially over time.

If this car is street driven and you want a good tune and want to enjoy it be sure you have a distributor WITH VACUUM ADVANCE.
Both the mechanical advance system and the vacuum advance systems will want specific custom setup to work best on this STREET tunnel ram car.

[F-BIRD'88]

Looking at your picture I do not see any fuel filters at all.
You need 2 of the paper element OEM style and quality inline fuel filters. These are not expensive.

99% of the pretty aftermarket hot rod fuel filters are JUNK.

EXCESSIVE fuel pressure and CRAP or missing fuel filters ='s flooding and agravation and potential engine damage.

I see a excessive amount of rubber fuel line.
This is a big FIRE HAZARD. Fix it. Especially at the front of the motor near the fan and drive belts.
This will not pass tech inspection at any dragstrip or any MTO/DOT vehicle safety -mechanical fitness inspection.
Do yourself a favour.....

[vht]

Fuel line is push loc hose and I have a large filter on the frame rail right before the pump. Fuel pressure is regulated to 5 1/4. 1850's on it now were set up for a 2x4 intake, vacuum secondarys were eliminated, a guy in New Jersey done them and I bought them from someone on here.

[F-BIRD'88]

If the vacuum secondary system has been eliminated on those carbs there will always be a flat spot/throttle response issue as you get into the secondary throttles on acceleration. Especially if auto trans with near stock torque converter and or modest rear gearing.

Locking out the diz mechanical advance system may help some... But will not fix it.

Replace the rubber line with hard line.
Get the fuel filter away from the exhaust
Should be 2 fuel filters. 1 for each carb.
If mechanical fuel pump the filter (s) goes after the pump. A dead head style fuel pressure regulator is not best to avoid flooding on a street car.
A return style regulator with return fuel line is much better especially if regulating down from high 15 psi (of a race pump) to 5+/- psi for the street carbs.

A 15 psi race pump will cause more problems than worth on a street car with a dead head regulator set up.

[F-BIRD'88]

Unless you can find a sucker those carbs as is are not worth peanuts as they are.
Eliminating the vaccum sec system was a bad move.
If you want double pumper holley carbs on it get double pumper carbs...
I hope you did not pay much for these carbs...
Sorry....

[jeff swisher]

I thought vacuum is what keeps the metering rods down and in a low vacuum engine you need the lightest shortest spring to keep the rods down. My engines run maybe 6-8 inches vacuum hot at idle and I’ve been running the spring set up as described above. Have I got this wrong? Don’t understand why one would put a second spring (pen) inside the step up springs. In my mind this would work opposite to what is needed on a low vacuum engine. Or maybe I’m totally misunderstanding this in which case I’ll blame it on dementia.

You are correct in your thinking.
I posted my engines have 11" or more idle vacuum and I needed a stiff spring.
My cruise vacuum is in the 16+ range.

I have ran 7.5 psi on the Carter AFB/Edelbrock, Holley, Rochester , and Motorcraft carbs for over 30 years and never had any flooding issues.
Holley used to sell a kit to eliminate the vacuum and make the carb a mechanical secondary.

We used to do it with a screw in the secondary linkage.
It works and no bog issues that I remember..I do remember they went quicker and faster when we made them mechanical.

Of course I ran a lot of timing 18-22 initial and 38 or more total all in by 2000-2200 rpm.
A lot of the bog people experienced was timing related as most of us know.

Don't toss stones at someones carb until you have ran it.
I have seen the 650 AVS on the dyno and it was awful.
Needed a lot of help. Slapped on an older 600 Performer and it cleaned up everywhere. Not what the customer wanted though.

Want a really great performing annular booster carb look no further than the old Motorcraft 2 barrel.
A bit small though may need a couple of them

[F-BIRD'88]

There is more difference between a #1405 carb and a #1406 carb than just the primary jets and rods.
I believe the idle circuit calibration (IFR, air bleeds, ect) are set up different on each.
You want to start with matching carbs.
The difference is in the different primary booster clusters fuel metering orrifices of each.
If using these mismatch carbs as a pair on a tunnel ram be prepared to need to dig into the idle circuit set up so they match and are correct for the job.

[vht]

Carbs run great, need to find another 1405, I put the same jets and rods in the 1406 as the 1405. Going to go to the stiffer step up springs.

[F-BIRD'88]

You could just swap the primary booster clusters from another 1405 carb so they both match.
Then you have a baseline to fine tune from, as required.
But good to hear of your progress.

It is unfortunate that the primary booster clusters are not offered as catalog replacement service parts.
Especially the recent annular style boosters .
Might call Edelbrock .