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Author Topic:   Rochester 2 Barrel
Hatcher13
Dirt Roller

Total posts: 16
posted December 12, 2004 09:54 PM  
Was there a certain year that has the best Rochester 2 barrel? Any tips and tricks to blueprinting them that anyone wants to share?

fastorange67
Dirt Roller

Total posts: 9
posted December 13, 2004 01:26 PM  
I would be intersted in the same info.

didn't the 69 impala 327 have a large 2 brll.

KPLugnut
Dirt Forum Champ
Total posts: 1019
posted December 13, 2004 02:10 PM  
I don't think any of the old 327 engines had large bore carbs on them. Most were the 1 5/16" venturi.

Many different vehicles and applications came with the large 1 3/8" venturi body 2bbl carb.
Grain trucks, old heavy duty dump trucks, even school buses for a SHORT time.
The Mercruiser 4cyl 2.3liter marine engines also have them. In fact, that's probably the best one out there, but a lot still needs to be changed internally for use on a dirt car. That carb number is 17087107, if memory serves, but there were numerous others used by Merc, too.
Another that comes to mind is the 1971 Pontiac 455ci cars came with a 2bbl option, and that was also the "big bore" carb.
As for asking for what numbers on the carbs to look for, well, there are literally dozens, and even sometimes they could fool ya.
Carbs ending in "118" MOST of the time are the large one, but I've found some that are not. That depended on the year/make/model of the carb's intended use. I've seen carbs ending in "362", "342", "108", and others just to name a couple.
In a nutshell, the easiest way to find one is to ask those of us that have either cores or finished race-ready ones in stock.
There are also collectors out there with them sitting on the shelf. Sometimes hard to find, but not THAT hard...

Hope that helps....

Kinetic Performance

[This message has been edited by KPLugnut (edited December 13, 2004).]

Blackgold
Dirt Full Roller

Total posts: 71
posted December 13, 2004 09:07 PM  
KP, while on the subject of carb size, Is it better to use the large bore carb 1 3/8 venturi to begin with or is it just as good to use the some of the smaller ones that have been bored out to 1 3/8? I've got one that has been bored, and it seems to run as good as the stock large bore that came off of a truck. I don't think that it has as large of float bowl though.

rockinron
Dirt Full Roller

Total posts: 30
posted December 14, 2004 07:49 AM  
I have a big 2 barrel for sale if you are interested.It does need rebuilt because it has been sitting. But it really has been hogged out. I can send you a pic or two if needed. $125 + freight. email me. rockinron@earthlink.net


KPLugnut
Dirt Forum Champ
Total posts: 1019
posted December 14, 2004 08:09 AM  
Blackgold,
I prefer to use "unmolested" carbs, especially in classes where rules require "no visible modifications", but either way of building an 1 3/8" venturi carb will work equally well IF the builder does it right.
The volume of fuel in either bowl isn't different enough to be a concern, usually, as long as a smaller brass float is used in the smaller bowls, but we've built tons of them either way and never had fuel starvation issues.
When we do enlarge smaller carbs to the 1 3/8" venturi (or larger in our outlaw ones), I prefer NOT to start with a big bore carb, as they are the harder ones to find, so we use the more common smaller ones and "molest" them, and save the OEM big bore ones for where classes require NO machining or modifications.
FWIW, almost all the carbs you see in catalogs are smaller ones that have been enlarged. And almost all the ones we've seen do NOT have the proper work done to restore the right venturi shape after boring. They seem to just shove an 1 3/8" end mill down thru and then de-burr it and do a stock rebuild and call that a "racing carb"....it's vastly different than what we do inside...

fwiw, jmho....
KP

Todchester
Dirt Roller

Total posts: 23
posted December 14, 2004 02:08 PM  
For those interested in Rochester 2bbl info..pm me and I will do what I can to help.

Blackgold
Dirt Full Roller

Total posts: 71
posted December 14, 2004 09:40 PM  
Thanks KP. That answers my question. The molested small venturi carb that I have appears to have a properly shaped venturi.

bejamin66
Dirt Full Roller

Total posts: 27
posted December 19, 2004 02:16 PM  
If your looking for a person to rebuild or find a big bore carb. This guy has done a lot of IMCA hobbys carb which I have one of his and has never failed me.
His name is Randy Wienholds in Newell,Ia
1-712-272-3557

bryanb30
Dirt Freak

Total posts: 243
posted December 19, 2004 04:41 PM  
my 2 barrel has a bowtie with the letters "BC" on the inside of the bowtie is this the baycity carb ive heard of? and is the baycity carb better than a regular one?

KPLugnut
Dirt Forum Champ
Total posts: 1019
posted December 19, 2004 04:59 PM  
Not necessarily. BC is just the model/version of the 2G. There were good ones and "regular" ones. Then again, there were good ones and "regular" ones in many years, on many vehicles, and used in many different applications.
What #'s are on the side of the bowl? That will tell you details about the carb.

KP

MetricMonte
Dirt Maniac

Total posts: 111
posted December 19, 2004 07:02 PM  
I think mine says BAY CITY in the Bowtie, not sure what difference that makes...

KPLugnut
Dirt Forum Champ
Total posts: 1019
posted December 19, 2004 07:05 PM  
NO difference at all. That's just the logo of the Bay City, MI plant where the carb was originally built by Rochester Engineering.

KP

    

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