Carb/intake upgrade from 2 to 4 barrel?

[kipche 10]

Hello,

 

I am a new owner of a 1969 Mustang, with a 302. It's a family car that has had alot of work done over the years. The engine is not original, but has approx. 30-40k. However, it still has a 2 barrel carb, and someone recommended I change to a 4 barrel w/ Edelbrock intake. Can anyone provide any information and/or recommendation on this? I don't know much about this, so any feedback is appreciated! Thanks in advance,

 

Chris

[bigperm2 10]

On a stock motor, you probably won't get a huge performance increase, but it will be a fun upgrade, and new carbs can solve problems caused by worn out carbs. I would recommend to spend the extra cash for a performer RPM or equivalent intake. I have read that the performer is as good as stock, but made with aluminum. I would also recommend a 600 cfm automatic choke carb, and I personally am a fan of holley carbs, but many others have had good luck with edelbrocks. Do you know what cam was installed in with the rebuild? If you are feeling bold, a cam swap would compliment the 4 bll well (assuming a stock or cheap replacement cam)

 

As far as the process to do the swap. Follow the instructions that come with the intake. It really isn't rocket science. They should be detailed enough to follow. And if followed, you will have good results. The key is to try not to let debris fall in the lifter valley while the intake is off, and to get a good seal on the intake valley gaskets.

 

BTW, welcome to the forum!!

[foothilltom 33]

Hey Chris, bigperm has you on the right track, but I would just add that my boy had a real positive experience with his 4bbl carb and manifold upgrade over xmas on his stock 2bbl 302. We went with a Edelbrock Performer intake from Summit Racing and a 600 cfm Holley bought rebuilt from a family friend. The boy reports much better throttle responsiveness and medium-speed accelleration with the secondaries kicking. I only drove it a few times (more on that in a bit) after the upgrade, and I agree it performs quite a bit better and sounds meaner in the bargain (he had already upgraded to dual flowmasters).

 

A few words of caution:

 

Installing the manifold is not hard, but getting a good seal isn't trivial. Stuff every orifice of your intake tunnel with crumpled newspaper after removing the old intake so stuff doesn't get in while you're cleaning up. Make sure you clean any remaining gasket material from the block. Take your time with this...use a paint scraper and get it all. Installing the new gasket is the only "trick". It has to be done right so you don't get vacuum leaks. A skilled friend comes in handy here as you can gently lower the new manifold on straight w/out moving the gasket around.

 

Torque the bolts to exacting specifications using a "inside-out, circular" pattern. Snug them a little bit at a time and move on to the next one. Repeat this until you are at the recommend torque (which is about 18ft-lb if memory serves for a Performer intake). Don't go nuts on these as you can warp your manifold.

 

With all of these changes, you will need to be patient about re-tuning your engine. With the carb swap, you'll want to verify your floats are set correctly and idle-mixture adjusted properly (there's lots of threads that discuss these but folks can help you here too).

 

Getting your fuel delivery tuned just so takes some time. If it's a new carb, it's probably already jetted and tuned correctly, so you may get lucky and just bolt it on and go. If it doesn't run right, don't lose hope...it's just a few adjustments away.

 

Case in point: it took me and my boy several weekends to get his 302 purring along after the upgrade. We didn't have any vacuum leaks, but we had to mess with jetting, accel pump, vacuum advance springs, idle-mixture, timing, to name a few.

 

Best of luck. It's a fun upgrade.

 

Tom

Edited February 25, 2010 by foothilltom

[Max Power 74]

I think the Performer is a better choice unless you are going with cam and cylinder head upgrades as well. The RPM manifold is designed for an rpm range that is above what an otherwise stock 302 is really capable of. Besides, it's cheaper.

[PROJECT222 10]

The first time I changed an intake on a 302 I was young and didnt take into consideration that the water passages run through the intake. I put the gaskets on dry and all said and done had to undo all my hard work and put sealer around the water ports on the heads and intake.

 

It's been a long time since I've swapped an intake and am about to do so on my 351W and assume the setup is the same can anyone advise on the best process to install the gaskets, I'm sure this could be helpful to Chris as well.

 

http://project222.wordpress.com/

[LoneWolf2U 136]

For a budget build, I used an Airgap intake (yea the cheap china made) with a 1in spacer with a holley 600 vac sec sitting on top.

Tossed on a pair of headers and it has very good responce at both low end and top.

 

As for intake installing, ensure a clean mating surface on both heads and intake. use sealant around the water ports and bolts a dab at the ends of the valley gaskets.

When torking it down, do it in stages. 1st snug tight, 2nd 15/20 3rd 25 and a 4th final tork to setting.

[Fordrevhead 29]

For a budget build, I used an Airgap intake (yea the cheap china made) with a 1in spacer with a holley 600 vac sec sitting on top.

Tossed on a pair of headers and it has very good responce at both low end and top.

 

As for intake installing, ensure a clean mating surface on both heads and intake. use sealant around the water ports and bolts a dab at the ends of the valley gaskets.

When torking it down, do it in stages. 1st snug tight, 2nd 15/20 3rd 25 and a 4th final tork to setting.

 

ProComp Motorsports China Edelbrock Airgap copy from ebay? Anybody else had any experience with those?

[very fat and very dumb 40]

I was talking to my machine shop guy the other day, he is working on my 351W. He is such a Ford guy his crap is blue, he says unless I'm putting something more aggresive that a RV cam in it don't waste the money on an aluminum intake.

 

I am curious to see what Slime has to say about this.

[Fordrevhead 29]

If it was a 351C-4v they had good flowing iron intakes, but the Windsor iron intake is not very good. An RV cam? Are you towing something? Low end torque but you'll lose high end rpm and hp.

[very fat and very dumb 40]

The engine is for the wife's convertible, beleive me, the last thing she needs is high end rpm's and hp. I was thinking a mild cam but not much more, I'm not sure if she'll even get headers, maybe that's why he said not to waste money on the intake.

[Fordrevhead 29]

ah yes, and the msd with the rev limiter chip ;)

[LoneWolf2U 136]

If it was a 351C-4v they had good flowing iron intakes, but the Windsor iron intake is not very good. An RV cam? Are you towing something? Low end torque but you'll lose high end rpm and hp.

 

68 Cougar 2900#

It has not been on a dyno so no real numbers, Just a seat of the pants feel.

66 289 .030 flat tops with stock 68 heads with ports cleaned up,

roller chain/gears stock valve train.

Melling rv cam, Nice easy lope at idle. Makes it sound like a BB.

Procomp airgap 1 in 4 hole spacer, 600 vac Holley.

Flowcomp headers hooked to 2.25 to magnaflow with 2.5 over the axle tailpipes.

C4 trans with shift kit turning a 2.75 dogleg. (for now)

 

All eng Parts off Fleabay, timing chain, cam/lifter, intake, headers, gasket kit under 600.00 to my door price.

 

A better Starting/running combo than stock 4V iron intake without headers and has good throttle resonce from 1500-5400.

The 2.75 rear is slow for off the line starts, but from a 20mph roll, It powers the Cougar quite nicely and still get 18mpg.

 

With a 3.50 tracloc it would be a tire fryer. :biggrin:

 

Ps. the intake change alone pulled 20# off the frontend weight, so it was worth it.

Edited February 27, 2010 by Mach1Rider