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Author Topic:   carb question?
dirttrackin94
Dirt Maniac

Total posts: 136
posted December 20, 2005 11:31 AM  
i bought a new trick 2bbl carb for our b-mod a couple weeks ago.it was built by c & s specialist.the carb started out as a 350 cfm 2bbl.it has had the choke horn milled off,50cc accelerator pump,brown pump cam,the butterflies were cut to 1 3/4,the bore is tapered,the bottom is 1 3/4 and the top is i beleive stk diameter..it is a annular venturi carb,the venturis are polished and have little bitty holes all the way around the top,the throttle shaft was milled and the screws were counter sunk for airflow,i am unsure of what they did to the metering block..my question is around what cfm will this carb flow.i have a 12:1 406ci motor with iron eagle heads on it,is the motor over kill for this carb or will it work out ok?thanks for any help.

KPLugnut
Dirt Forum Champ
Total posts: 1041
posted December 20, 2005 11:37 AM  
C&S builds those carbs from the old 6425 2bbls and in that form, the carb is rated at 650cfm. That should be enough for that motor, but cam choice with 2bbl motors is as important as anything.
The 6425 carb originally came with 1.75" baseplate, but not the milled shaft (which doesn't add a ton of cfm but does help).
As for "what they did" to the metering block, it would depend on the application, whether or not it's the OEM block on there in modified form, or is it a block that is based on the HP series Holley block (not likely, as C&S doesn't do that usually), or is it a custom billet piece (typical of Quick Fuel, etc, and similar to the Proform blocks).
Anyway, without seeing it myself, I couldn't tell you how much is "no longer stock", but to answer your original question, the carb will work fine if you tune it properly.

KP

dirttrackin94
Dirt Maniac

Total posts: 136
posted December 20, 2005 11:53 AM  
thanks alot for the answer,ive been told by a few poeple that it should flow around what you have said.the metering block isnt billet i do know that,but i cannot tell weather it is stk or an hp series metering block.again thanks for the answers.

one last thing.what cam would you recomend?my specs are this carb,and a 406 with iron eagle heads.im wanting to turn in the 6500-6800 range.i have an elgin 1090-p cam??

KPLugnut
Dirt Forum Champ
Total posts: 1041
posted December 20, 2005 12:13 PM  
I would always recommend a custom grind from Camcraft. Something in the 246/252 or 250/254 duration depending on track length, etc. and run 1.6 or 1.7 intake rockers and 1.5's on exhaust.
Talk to Charles at Camcraft and he'll get you set up.

KP

James Ott
Dirt Maniac

Total posts: 178
posted December 20, 2005 03:17 PM  
Hey Dayton how come peoples come to you after they buy the carb?

KPLugnut
Dirt Forum Champ
Total posts: 1041
posted December 20, 2005 04:55 PM  
Maybe because I don't have that million dollar marketing budget to tell the world that we're also a stocking Holley, Rochester, Carter/Edelbrock etc dealer as well as a dealer for about every brand name of aftermarket or racing part there is?
I wish I knew the best way to let guys know that without "spamming" the forums or sounding like a pompous insurance salesman. :-)
We build new stuff, repair old stuff, salvage what many view as "junk", and stand behind everything we do. And quietly, and quickly, we are accumulating a huge list of championship-winning customers from the most entry level up thru Busch North series, etc.
But rather than "toot" my horn, I'll just say that if ANYONE has a carburetor need, or about any other need, just ask. We can probably save you time, money and headaches.

Dayton Umholtz, co-owner
Kinetic Performance

dirttrackin94
Dirt Maniac

Total posts: 136
posted December 20, 2005 08:21 PM  
good bit of info kp,i never knew that i always just thought you was a carb ''guru''..lol...trust me if i had known that i would have gotten stuff from you,i think it is only ''right'' to help those that help you,your a great help on the boards and im sure im not the only one who appreciates it..

A. Bighurry
Dirt Full Roller

Total posts: 54
posted December 20, 2005 09:59 PM  
KP, it couldn't be a metering block from an HP carb because the 6425 uses an accelerator passage transfer tube with o rings and has the accelerator pump passage hole moved over where it meets the fuel bowl.

KPLugnut
Dirt Forum Champ
Total posts: 1041
posted December 21, 2005 06:25 AM  
We convert them to HP blocks all the time. Milling the O-ring tube in half, to the proper length and installing jus that part before installing the metering block has been done for years.
We also block the timed spark vacuum port hole in the main body, as HP blocks have the idle fuel circuit lined up with that.

When we build 'em, we build them with all those details (and many others) taken care of.

KP

dirttrackin94
Dirt Maniac

Total posts: 136
posted December 21, 2005 08:08 AM  
I CAN TELL YOU THAT THERE ARE A COUPLE OF SPOTS ON THE METERING BLOCK THAT HAVE WHAT LOOKS TO BE SOTTER IN THEM TO BLOCK THEM OFF,OR IF NOT SOTTER IT IS SOME SILVER STUFF.THIS MEAN ITS AND HP METERING PLATE?THANKS KP!

KPLugnut
Dirt Forum Champ
Total posts: 1041
posted December 21, 2005 08:13 AM  
No, that doesn't mean it's an HP series block. It would have "HP" in the circular indentation on the side of the block where the holley part # is.
Those places where they've plugged things, are simply lead "slugs" that are used commonly by carb builders (the same ones used by Holley and Rochester during OEM buildup).
What you've most likely got is a slightly altered standard 6425 block or standard 4412 block used on that 2bbl.
And I bet ya paid GOOD $ for that too. :-)

KP

dirttrackin94
Dirt Maniac

Total posts: 136
posted December 21, 2005 10:04 AM  
ACTUALLY I GIVE $200 FOR THE CARB FROM A BUDDY,CALLED C&S WITH THE NUMBERS ON THE CARB AND THEY SAY IT WAS BOUGHT IN OCTOBER,SO I THINK I GOT A GOOD DEAL,I HOPE ATLEAST!I JUST COULDNT GET THEM TO TELL ME ANY INFO ON WHAT WAS DONE OR ANYTHING.ABOUT WHAT WOULD IT COST TO BUILD A CARB LIKE THIS?

THE METERING BLOCK HAS CUTOUT INDENTIONS ON ONE SIDE OF IT,WHEREAS ALOT OF STK 4412 I HAVE SEEN THE METERING BLOCK IS SMOOTH ON BOTH SIDES,IM SURE IT IS A MODDED HOLLEY METERING PLATE,ITS THE SAME COLOR AS THE BOWLS.

[This message has been edited by dirttrackin94 (edited December 21, 2005).]

[This message has been edited by dirttrackin94 (edited December 21, 2005).]

KPLugnut
Dirt Forum Champ
Total posts: 1041
posted December 21, 2005 10:06 AM  
OK, yes, that's worth it. I was under the assumption you'd purchased it brand new.
Sorry about that. :-)

KP

A. Bighurry
Dirt Full Roller

Total posts: 54
posted December 21, 2005 09:48 PM  
KP, the newer metering block would be a nice feature. We found out about the differences about 15 years ago at the track when we tore a gasket and couldn't find anything but the ones used on the newer metering blocks. Early night that time.

CLBaker25
Dirt Freak

Total posts: 223
posted December 23, 2005 06:53 AM  
dirttrackin94,

Depending on what RPM range you are turning it, I think that you will be happier with a 406 than a 350. We like the longer stroke and better low end power of our 406 -vs- a 350 with the small carb. We could never get that much RPM out of the little carb in an IMCA stock car.

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