I just picked up a dual carb intake for my Chevy 250. It came with 2 Rochester 1 barrel carbs. They need to be rebuilt. I don't know the year of them. Their is supposed to be a ID tag on them but they are long gone. Can anyone tell me what year they are? Here are some pics. Thanks, Todd ***update*** I found 2 different numbers stamped on the baseplate. 4525 is stamped right where the baseplate meets the intake 57 is stamped where the baseplate meets the carb body. Thanks again!!
Ohhh, Model B's. Nice that"s what I got on my 235. Great carb. I needed to lower the float about 1/8 to stop the slossing and leaking out of where the acel pump rod is. I'm jetted for mileage now, about a 57 I think, gets 25. Had big ones in it before an was at 16 mpg. Very easy to set up and keep the linkage equal for duals non progressive.
What year, ?? don't have a clue other than mid sixties. The choke linkage and fuel fittings are the same as what I got and were supposed to be a manual choke truck carb. And somehow I got written down here that a Hygrade 123A Kit is the one for them. I think a lot of the minor parts and pieces that are in the kit are very universal.
Thanks for the info. Glad to here they are a good carb. I will see if I can find a decent rebuild kit for them. Hopefully someone can give me a better idea of the year, but like you said alot of the rebuild parts are universal. How hard is it to find jets? are they the same as the one used in 2 and 4 barrel rochesters? Thanks again, Todd
Based on the throttle bore, could be a 7023021, a 7023011, or a 7023017 according to my '63 truck manual. Fit the 230cuin motors, maybe others in later years?
PM carbking. He'll be able to tell you exactly what they are. He also sells better kits than the vato zone. Even if you don't buy his kits, it pays to know exactly which Rochester B you've got. There were several different ones, otherwise visually identical. Kits have slightly different parts for the different B's.
Kit wise, there is only 2. 47-62 with a leather accelerator pump, and 63-66 with plastic. Take it apart and see. for example http://www.classicparts.com/searchprods.asp?searchstring=carb+kits&pagenumber=3&val=0 To know if the carbs are the same or not, measure the throttle bore and the venturi diameter. If these aren't the same, then they will not flow at the same rate. Other things like jetting can be changed to be the same.
I just measured the both throttle bores and both veturi dia. They are the same on both carbs. Also, I pulled both accelerator pumps. They are rubber and plastic. So I assume it is a 63-66. Todd
Todd, when I was rejetting mine I used jets from my whole stock of old rochester carbs. All the threads were the same 2G's and Q jet. But the heads and lenghts were different. but I used the same pairs tpgether. I finally bought one pair from summit, probably a Q jet style, to fill in a gap and don't really remember which style is in there now but it is deffinitly not a B type jet. It should run OK, really good actually, on the factory jets. Mine did and allowed to get the whole system working good before fiddling with fine tuning the high speed mix main jet size.
seems to me the id tags go bye bye after the first rebuild- as far as jets i usually buy swapmeet carbs for 5-10 bucks for the jets,parts - not sure if my auto parts store can get them -for the early model b carbs the hygrade 123-a kit that was stated in a previous post comes to mind- the later ones i will have to check at the parts store- ive got a few of those if you need any parts -joe
Yup, 63-66. NAPA or O'Reilys will have kits cheap enough. just pretend they are for a 1965 230 truck engine (or similar) and you will be fine on getting kits. The earlier B's typically had a 57 or 58 jet in them. The article over at Inliners about how to set them up for a 2x1 setup talks about going down to a 51 or 52. I would suggest installing an air/fuel gauge if you really want to dial it in. Rochester 2GC jets are the same as the ones in a Model B 1bbl. I believe I ordered mine from www.Carbsonly.com
I am in a similar situation. I am running a 250 with 3 of those. Napa offers a few different kits for them, the main difference that I have found being the plunger. They can order you the correct plunger if you can't find the kit with the right one, only about $2-$3 for the plunger. I think with that armiture on the side it came off of a truck engine. That model carb was introduced in about 62 or 63 when GM switched to the 194, 230, 250 style inlines. They made them for a few years until they went to the Mono-jet. GM had a similar looking carb on the 235 style inlines but it was a little bit smaller diameter. Please correct me if I am wrong on any of that. That's what I have been able to gather so far on them.
There was a larger sized Rochester B carb on the 261 vs. the 235. I'm not sure if this is the same carb as on the later 230. The carburetor doctor lists five different kits for Rochester B's which would lead me to believe there are at least that many different variations. I don't have any paperwork to back that up.
The Carburetor Shop (carbking on here) says Rochester made 141 different B type carburetors. http://www.thecarburetorshop.com/RochestermultipleB.htm This is also great info for a multi Rochester B set up.
JFYI, even my 292 has a Rochester B. Pretty much the same design on the exterior, but different bowl venting and larger venturi and throttle bore. So, if your want an Rochester B that really breathes, look for a 7023013, throttle bore measures 1 3/4, all others {in my '63 manual} show 1 9/16. If anyone knows the OE jetting for the '63 292 2 ton info, I am curious. No telling if my carb is original, and I think it isnt. Pushing my behemoth along, the 292 likes a touch of choke, like it is running lean {maybe someone stuck a light truck carb on it?} I would like to jet it correctly for best power and economy.
Unfortunately, it is extremely difficult to identify a Rochester B once the tag has been removed. And we offer 33 different rebuilding kits for the various model B Rochester carbs. Jon.
I know this is an old thread, but maybe Jon will see this post. If 33 kits are available for the Rochester B, and the tag has been removed, how can you order the correct kit ?
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