The Stovebolt Site Forums The Shop Area Engine Shop stupid 2x1 & split exhaust question

A neighbor just gave me two old single barrel Rochester B carbs that he had laying around his garage. They are still in the box and appear to be in great shape. Can these two carbs be used in a dual carb set up for my engine ??? (59 trck original 325)

I see a lot of guys running dual carbs with split exhaust. Could I use these carbs as a starting point or is there a better carb option. (I don't have a lot of $$$ so anytime I get free stuff I would prefer to use it). Are he Rochesters what most people use?

Also, I have a local guy that says he can split my stock exhaust manifold for me. Is this recommended? Is there a reason why I should buy Fentons or some of the other name brand? Are they better than splitting my stock exhaust?

i like the stock 6 motor myself they run so smooth if i wanted a rod id go with a v8 a built 6 sucks gas and two xe. pipes to get in the way just my 2 cents had a 6 with a racing cam ounce

I'd say if the freeby carbs are new or rebuilt, this is a huge plus. Most are so worn around the throttle shafts they suck air. Also make sure they are exactly the same, bolt spacing to manifold also check throttle bore size. They made a zillion Rochesters for every car and truck, so check this out. Install rebuild kits, read the instructions closely, especially check floats and float setting. Make sure jet sizes are also the same.
If your local guy is really good with cast iron, I'd let him split the exhaust, this way you know it will fit your motor.

i had my brother split my maniford several years ago and have had no problems with it. good way to save money when you are working on a budjet. great sound with glass paks and straight out the back!

Thanks all-

I'm pretty sure that the carbs are exactly the same as the stock one.

QUESTION: Could I split the exhaut for now and run it with the single carb... until I get the set up together for the dual carbs?

You can run a split exhaust with a single carb. It will work just fine!

The hard part is splitting the exhaust manifold or finding someone who can do it. It has become a lost art!

Fenton cast iron header is a good bet!

Your Rodchester carbs are a good start for dual application.

There is a great shop that will split your stock manifold and their work is first class. Contact Mike at Kansas Kustoms (316)663-3256. You can get this done for $185.00 includes return UPS, per his latest ad the 12 Port News.

Just for kicks I had a local shop take my single pipe off of the manifold and pipe it into a flowmaster, then out with a y and two pipes out the back. Rumbles just enough and I didn't have to mess with the manifold.

Is there a 2bbl available that could be mounted to the Offy intake (2x1) that is progressive? Is this kind of setup recommended? Do you need to beef up the cam to support them?

I've had good success with talking to the guys at Clifford Performance. www.cliffordperformance.com
They reccommended a mild cam, a progressive 2 barrel and real tube headers. They said splitting the manifold or running Fentons doesn't really gain you much. He said dual carbs are alright for a show truck and such, but said to stay away from them on a daily driver. They usually go out of tune easily and suck gas.

i have been running dual carbs for three years now, and no problems. i am not a mechanic but installed the fentons and carbs myself. the fentons made the biggest improvement more power and response even with 2.73 nova rearend. this means i can delay a new ratio for awhile and put the money elsewhere on the truck. my 2 cents. ron

I run 2 Rochester B carbs on a Fenton intake with Fenton cast iron headers, and I get better mileage with the 2-carbs. than the stock single. Maybe because it has more power and I don't have to have my foot in it all the time? I did have to bush the bases on the carbs as they were worn out and sucking air like Jim said.

I'm running two NOS Rochester 1 bbl. carbs on my 261 through an Edelbrock 2 x 1 intake. They are small base carbs NOS carbs. I have made it a point to be sure I have no vaccuum leaks and that they are jetted as small as possible without sacrificing performance. I also recently have discovered that the small 1 bbl. foreign made chrome air cleaners with the small paper element do not allow enough air to enter the carb throat and they tend to choke the carbs. I have moved to a larger air cleaner set up and it has improved gas mileage.

Repop Fentons are no better than properly split stock manifold & splitting is cheaper too ~ retain the heat risor flapper for good cold weather warmup , Fentons you gotta plumb in exhaust heat , poor fittment problems caused by crappy quality control etc. you decide .

Rochester 'B'series carbys are dead simple and easy to fix adjust and so on , carbies DO NOT got ' out of adjustment ' ~ _ever_ that's just not so .

Properly set up , dual carbies will _always_ provide better fuel milage and power as the fuel is more accurately measured .

Folks who know , will says do it , folks who don't will say it's bad . bigger carby (2BBL) in center of manifold doesn't meter fuel evenly to that long engine so middle cyclinders run richer than end cylinders , faster yes but not such good
drivability as multi - carby set ups .

There's a page on The Inliner's site about modifying the Rochesters for maximum effect , I know lotsa folks just ensure the jets & such match (critical) then plop 'em on , balance and GO .

I say DO IT & have fun ! .

Yeah...I'm trying to soak in all of the above. I've got a stock exhaust manifold that someone split before I got the truck. It's been running great and sounding even better. Problem is, the new exhaust elbow added onto the manifold is starting to crack at the weld. Anyone have any ideas, short of starting all over with a stock manifold and having it split? I wanted to get my exhaust manifold jet-hot coated. I've been looking at the various custom headers available, but haven't seen a custom dual exhaust one yet that'll heat the floor of the intake manifold.

Kansas Kustoms says they don't split manifolds anymore. Mine is missing the heat riser and probably impossible to remove from the intake without busting bolts, but if someone can post a url to a place that does fix and modify manifolds, that would be a heroic gesture indeed.

"Is there a 2bbl available that could be mounted to the Offy intake (2x1) that is progressive?"

Jerry: I thought you were using the Holley Weber 2 bbl's on your Offy intake. They are progressive according to Langdon. It's what I run and once properly tuned seem to work just fine.

I'm running dual Holley 1904s on an Offy intake with Fentons, no heat riser or heat plumbed to the intake, it's only bad on feul when it's cold. Once it warms up theres no problems. I was getting poor milage, but that was caused by an incorrect float setting. I would suggest using the bigger filter housings instead of the little 3" ones, you'll get better flow and more filter area. I used 6" mr. Gasket housings with K&N filter elements.