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Author Topic:   STARTING JET SIZE
YAZ
Dirt Forum Racer

Total posts: 77
posted May 21, 2002 11:20 PM
IN MY CLASS WE HAVE TO RUN 2BARREL ROCHESTER
CARBS. I HAVE SIZE 70 IN MINE AND I CHECKED
THE SPARK PLUGS AFTER THIS WEEKEND AND THEY
ARE PURE WHITE NO COLOR AT ALL. I NEED TO GO WITH BIGGER JETS. DOES ANYONE HAVE A STARTING
POINT ON WHAT SIZE I CHOULD TRY?

SECOND QUESTION, I HAVE BEEN HAVING A LOT OF
TROUBLE FINDING JETS FOR THE ROCHESTER CARBS.
WHEN I CALLED GM IN MY TOWN THEY LAUGHED AT
ME AND SAID THEY HAVENT USED CARBS FOR TWENTY
YEARS. ANY SUGGESTIONS?

racer17j
Dirt Forum Champ
Total posts: 1565
posted May 22, 2002 02:43 AM UIN: 54865418
i use 72's as a starting point as for finding jets go to a hobby store and get a tap for gas powered r/c car spark plugs tap the holes and get a set of holley jets can get from 60-99 for around $35 for the set

KPLugnut
Dirt Freak

Total posts: 408
posted May 22, 2002 08:20 AM
We can supply you with any size Rochester jet you want, if you're interested. We are a supplier of all small parts for Rochester, Holley, Carter, etc.
As for jetting in your case, I'd go with at least a 74 Holley size.
In order to convert the Rochester 2G to a Holley jet, you'll need a 1/4x32 tap, available thru us, if you wish, or thru carb parts suppliers, or even a hobby shop as stated above.
Let us know if we can help in any way.

Dayton Umholtz, owner
Kinetic Performance
(sponsor of The Dirt Forum).

YAZ
Dirt Forum Racer

Total posts: 77
posted May 23, 2002 10:57 PM
THANKS GUYS.
I FOUND AN EXTRA SET OF JETS IN MY
TOOL BOX AND HAD A DRAGRACER FRIEND
SHOW ME HOW TO DRILL THEM BIGGER. I
WENT TO 73. I WILL FIND OUT HOW IT WORKS
SATURDAY. I SAVED THE OTHER JETS IN CAUSE ITS TO BIG.

KPLIGNUT,
HOW MUCH DO YOU CHARGE FOR THAT TAP, AND
HOW HARD IS IT TO DO. DO YOU HAVE TO DRILL
THE HOLES BIGGER FIRST?

KPLugnut
Dirt Freak

Total posts: 408
posted May 24, 2002 08:14 AM
Taps run about $6 plus shipping, and no, you don't have to drill the hole out first. Just run the tap in the existing threads, since a Rochester thread pitch is only slightly different than the Holley jet threads.
Let me know if I can help.

KPLugnut
aka, Dayton Umholtz, owner
Kinetic Performance

6pack
Dirt Maniac

Total posts: 128
posted May 24, 2002 08:37 PM
KP, do you keep miscellaneous Q-jet parts, such as power piston springs?

KPLugnut
Dirt Freak

Total posts: 408
posted May 24, 2002 08:49 PM
Yes, we can supply just about ANY Rochester, Holley, Carter, etc. part there is. In single quantity or in bulk.
Just let us know what ya need and I'll quote ya a deal.

Thanks for asking.


merlinmech
Dirt Full Roller

Total posts: 51
posted May 25, 2002 09:20 AM
kp, how about a complete carb with 1 3/8 bore?

KPLugnut
Dirt Freak

Total posts: 408
posted May 25, 2002 01:41 PM
Yes, we sell the large bore 2G carbs. We can sell an unrebuilt core, or fully race ready carbs. Prices vary obviously, and depending on what is done to each carb (we do every one individually for the engine combination it is intended for), the price can run from $250 to the top end piece at just under $400.

Just let us know what your needs are and we'll be glad to help.

Dayton Umholtz, owner
Kinetic Performance

RangeRover
Dirt Maniac

Total posts: 174
posted May 28, 2002 01:44 PM
KP Lugnut, here's my big question. Can you supply a Holley 500 cfm 4412 that will pass the normal tech inspections, but provides a power-producing advantage over a new one out of the box? This is an area that I feel one could improve in, but there are skeptics who believe that there's not much to improve on if the carb is already tuned properly for the application. This carb is our biggest power restrictor in our street stocks and I'm very interested in a carb that can offer more potential.

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