Inliners International Forums General Discussion Engines Monojet carb

My coworker gave me an uctual Monojet 1 barrel today, It will need a kit though.
What I am wondering is if it will be a better carb than the Rochester B model?

The Monojet is Rochesters replacement for the Model B. Is it going to be better than your Model B will depend on what the Monojet is setup for, do you know what it came off of? There also seems to be some concern as to what engine you have. If the side covers are 4" high it is a 230 or 250. If they are 6" high it's a 292. Hopefully there is a tag on the Monojet if your buddy doesn't know what it came from. Monojets can't be all bad they sell for $40-70 on !bay depending on condition. IMO they're better than the B. You need to do some research to get the right mix. My 2¢
Larry
68 C20 327/465 daily driver 4:56 och!
63 C20 292/420 Camper truck Detroit Locker 4:10 posi
65 C10 ? /powerglide Custom Cab AC,PB,PS,4xflash

I like the Monojet better than the Mod-B too, It has no tag so I will have to do some research when I pull it apart.
He also gave me a HOLLEY 2 BBL for FUTURE, Its brand new, mounted it and didnt like it putting it in a box. It sat for the last 2 years but when I need it after finding the new intake I want - I will have it.

Numbers on the monojet are 7034001 on the top of the carb.
on the side there is numbers stamped :
7029014 / 220 8 BB.

Randy.

The number on the side is the right one. A good parts store might be able to check it for you. Is the Holley a progrssive, like half a 4 bbl, were you have a primary and a secondary throttle. If so save it other wise find out what it is and,,, Some holley 2 bbl were real monsters.
Larry
68 C20 327/465 daily driver 4:56 och!
63 C20 292/420 Camper truck Detroit Locker 4:10 posi
65 C10 ? /powerglide Custom Cab AC,PB,PS,4xflash

"Quote" Whats the difference in towers from the ones I have plus the ones i got from you? Yours are for a V-8. This is really frusterating to find out its a SMALL 6 so long after I got it. I emailed my uncle and a couple friends to see if they still have theirs in the backs of their sheds. They all have nice LOW mile long blocks and one of them has a full complete running engine. See what they say. "end quote"
The V8 and L6 mounts are the same except for the 292. The 292 has the fuel pump moved back for some reason, so the moount on that side had to be moved forward. Hopefully you'll find a 292. I've been surprised at little cylinder wear there has been on what I expect are high mileage 292s. They are great motors, you'll like it.
Larry
68 C20 327/465 daily driver 4:56 och!
63 C20 292/420 Camper truck Detroit Locker 4:10 posi
65 C10 ? /powerglide Custom Cab AC,PB,PS,4xflash

Enough said, 292 is going to happen since I thought it was one already. I like the 6 better than a v-8 for some reason.

numbers show its a 1969 buick 6 250 .
http://www.thecarburetorshop.com/Kbuick3.htm

The two barrel is marked, R 7871 A / 4041585 0038
With ink stamp 5 409
under the bowl is 6R4772B
No other numbers anyplace.
It is half a 4, Progressive type. I will post a photo shotly.

http://community.webshots.com/photo/132285490/214673642PFtvlc
http://community.webshots.com/album/132285490kvjGkS/2
I cant find anything on the net containing any info on this carb.

See if this photo thing works.

and top view :

OK, that's the basics. What it doesn't tell you "The Monojet came in 3 sizes. The smallest has a 1-7/16" throttle bore and 1 7/32" venturi. It was used on 4 cylinder engines. The second largest and most common has a 1-11/16" throttle bore and a 1-5/16" venturi. This is the 250 carb. The largest has a 1-11/16 throttle bore and 1-1/2" venturi. It was used on the 292 in heavy duty applications. The throttle bores are the same on the 250 and 292 carbs but the 292 has a larger venturi. The small carb flows 160cfm - 250 carb flows 210cfm and 292 carb flows 250cfm." I swiped this from stovebolt.
You'll need to get some more info carbs to see what the differences are between the Buick and your truck. Such as jet, power valve size, I don't have a sheet on the carb handy to what else there night be.
Larry
68 C20 327/465 daily driver 4:56 och!
63 C20 292/420 Camper Detroit Locker 4:10 posi
65 C10 ?/powerglide Custom Cab AC,PB,PS,4xflash

Cool, thanks !
info is good to have when rebuilding these. It helped with the B model.

I don't know were you guys come up with the idea that the monjet carb is a better carb then the B personally I would go with a B carb.

I have talked to several old machanics who worked on Gm vehicles 30 years ago and they all say that the monojet carb has far more problems then the b carbs.

The only problems with the B carbs is that they can leak out the sides but there are whys to deal with that issue, there simpler carbs and been around since 1937 longer then monojets.

I switched from the B to the Monojet about 3-4 years ago. I haven't had any problems with it. My gas mileage increased by 2-3 mpg, perhaps that was because unlike the B, the Monojet will let you play with the fuel mixture via a power valve. Now maybe that can be done with a B too, just not as easy. Now there are some boards were recent discussions have been to replace anything with the name Rochester on it with a Carter or Zenith. What ever works for you.
Larry
68 C20 327/465 daily driver 4:56 och!
63 C20 292/420 Camper truck Detroit Locker 4:10 posi
65 C10 ? /powerglide Custom Cab AC,PB,PS,4xflash