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351w 2bbl to 4bbl & intake swap

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Blacktop

351w 2bbl to 4bbl & intake swap

Hi everyone,
I’m planning on removing the 2bbl carb and intake on my 351w and fitting a 4bbl Holley and Edelbrock intake. I’ll be removing the smog system and egr as well.
Has anyone else done this and did you have any issues with the swap?
Many thanks for any info,
Alan

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

When I bought Rusty, an '81 F150 w/a built 351M, it had an Edelbrock intake and a Holley 4160. It ran like a bandit at WOT, but didn't idle well and stumbled a bit when coming off idle. I had an Edelbrock 1406, which is also a 600 CFM carb, sitting on the shelf so I installed it. That cured the idle and off-idle issues, but cut back a bit on the WOT acceleration.

I'm not saying that the Edelbrock is better than a Holley, but those were out-of-the box carbs and one was tuned nicely for the application and one wasn't. Given that, you may need to dial the Holley in to get it to run "right".

But the Edelbrock intake is a good one, and the Holley can be tuned to fit about any application.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

reamer

Re: 351w 2bbl to 4bbl & intake swap

Been there, Done that!

Pulled over 50 lbs of emissions crap and installed the Eddy 4-v Non-egr intake and Eddy 4-V
Pulling the emissions was highly suggested by my Ford dealer.
Has he put it, "will run a hell of a lot better without that crap.....and it DOES

When installing the intake, use brake cleaner to clean the block where it mates to the intake.
Do not use the front and rear gaskets, RTV only, AND make double sure to clean the point there the heads, block and intake mate, clean it and then clean them again and again. This is where your oil leak will form within an hour of running

For some reason the oil pump shaft to the dizzy was too short! I had to find one @1/2 longer. make sure the dizzy will not spin free once installed.,,

51 Lbs of crap

Shiny....

And By the way, I ditched in the trash-can that POS HEI 1-wire, the shaft bering, or should I say, bushing, wore out in one season, got a replacement dizzy assembly, and that one toasted the module.

Went back to a Motrorcraft Dizzy and Duraspark II and never needed to look back! (thanks to Gary on the help wiring it correctly!)

1986 F-150 Flareside 4x4, 351, 4-v, ZF5 speed. AC, Cruise, Tilt, Slider, Digital clock, Radio, Lariat seat, Pwr doors/locks

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

In reply to this post by Gary Lewis

Thanks for the reply👍
I have done this swap before on a 302w in my mustang so I’m familiar with setting up a Holley to run. I use an air fuel ratio gauge to get the jetting right.
My only concern is wether I might run into issues with engine control module and fault codes etc. I think my truck has the computer controlled carb on it. Does the engine module also control ignition timing as well as the carb or are they two separate systems?

Alan

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

In reply to this post by reamer

Definitely a worthwhile mod Reamer, yours looks so much cleaner and I bet it runs way better too!

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

reamer

Re: 351w 2bbl to 4bbl & intake swap

Amazing how much better! 750 rpm at idle, 85+mph (installed a ZF 5-sp)
Don't even have the computer box, al went bye-bye...

1986 F-150 Flareside 4x4, 351, 4-v, ZF5 speed. AC, Cruise, Tilt, Slider, Digital clock, Radio, Lariat seat, Pwr doors/locks

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

In reply to this post by Blacktop

The computer has to be neutered, if not removed. If you have a computer it controls the ignition timing, and it will get its knickers in a twist when you remove ANYTHING and kill the timing advance. So the dizzy has to be replaced with a DS-II or HEI, although Ron/reamer tells you why you might want to go w/a DS-II.

If you pull the computer you have nothing to control the EGR, nor the TAB and TAD relays, nor ........ So everything Ron showed might as well come off/out.

Gary, AKA "Gary fellow": Profile

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

I have a hei module already so will source a duraspark distributor to replace the tfi one currently fitted.

Alan

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

I've missed something. If you have an HEI module and are looking for a Duraspark distributor, are you going to install the HEI module in the DS distributor? Because the two don't usually get wired together.

So, what did I miss?

Gary, AKA "Gary fellow": Profile

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

I was thinking of removing the factory tfi ignition if it would give problems with the engine control module removed. I would then replace it with a duraspark distributor and wire in a hei module like this:

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

Ahhh! That's what I missed - a lot of wiring and fabrication. That will work, and someone on here (Steve83?) recently posted a pic of mounting the HEI module in a gutted DS-II case.

But, I'd ask the question "why"? Why not just use a DS-II module? They are available at 'most any parts store should yours quite. And for the most part, spark is spark.

Gary, AKA "Gary fellow": Profile

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

Yeah, I might still use a duraspark module. Not 100% sure which way I'll go yet. Just bouncing ideas around my head😁

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

I tend to think about how difficult it is going to be to replace things, and an ignition module would be on a high-priority to replace if you were out and about. And, while you can buy and HEI module at a parts store, he easy will it be to replace it in a custom housing?

On the other hand, DS-II modules are available at any parts store or salvage.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: 351w 2bbl to 4bbl & intake swap

Administrator

Do like Lucas did, put it in an external heat sink case.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

In reply to this post by Gary Lewis

How much work is involved changing from a tfi ignition system to a duraspark 2 system? And is it easier than just wiring a duraspark distributor up to a hei module?

Alan

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

Alan - Now we need to write up the DS-II tab on the Ignition page. But basically you need to source a DS-II distributor, wiring harness, and blue-grommet ignition module. And then it is plug-and-play.

As for "just wiring a duraspark distributor up to a hei module", that's something I would be reluctant to do. And my reasoning is that you'd now have a one-off situation where a failure of the HEI module would have you stranded.

However, there are at least two ways around that. One is to make two of the HEI modules. For instance, if you gut a DS-II box to be the housing/heat sink, then make two of them and wire them with connectors so they can be easily swapped. Another is to make the installation of the module in the housing/heat sink such that the module itself can be easily replaced, and carry a spare module.

I'm not at all saying that an HEI module is more prone to failure than a DS-II box. Not at all. It is just that I don't want to create a system that is so specialized that when something in it fails I'm stuck and have to break out the soldering gun to fix it. Instead, I want an easy and quick way to get back on the road. A stock DS-II box is readily available 'most anywhere, as are HEI modules from what I read. But the DS-II box is an easy unplug/replug, so I'd make sure the HEI module is as well.

Gary, AKA "Gary fellow": Profile

Blacktop

Re: 351w 2bbl to 4bbl & intake swap

Sounds about right Gary. Being in the uk, neither ds2 modules or hei modules are readily available over here. I source my parts mainly from rock auto and ship them over. I will need to source a ds2 distributor and I already have two hei modules ready. But perhaps for simplicity, I might just buy two ds2 modules and have one as a spare.
Many thanks for all your help and info😊
Alan

1984 F150 XLT short bed 4x4 351w 4speed manual
1980 F100 long bed 2wd 300-6 3speed manual project truck
🇬🇧UK based truck enthusiast🇬🇧

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

I forgot you are in England. Over here the modules are available in many, if not all, parts stores.

If you go HEI don't miss that you need a relay since the module is power-hungry and you have to bypass the built-in ballast resistor.

For a DS-II harness, we have this outfit listed in Resources: American Auto Wire. I don't know anything about them, but we've had some feedback that the Painless harness isn't painless. And, it is expensive. So, you might try this one. However, looking at their instruction sheet, it isn't totally plug-and-play.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: 351w 2bbl to 4bbl & intake swap

Administrator

In reply to this post by Blacktop

Being in the UK, Lucas Constant Energy modules are the 4 pin HEI in a heat sink case. As a result using the DS-II distributor as a trigger and a Lucas coil could be an excellent fix.

Bill AKA "LOBO" Profile

Gary Lewis

Re: 351w 2bbl to 4bbl & intake swap

Administrator

Interesting idea, Bill. I did some reading on that module and it looks like several of the Jags used it. But, one listing had it at 165 Pounds Sterling, which has to be over $200.

Perhaps that's one specific to a Jag? Maybe there are cheaper ones? Perhaps that's cheaper than shipping a DS-II module over the pond?

Gary, AKA "Gary fellow": Profile