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| | | | Joined: Aug 2011 Posts: 32 New Guy | | New Guy Joined: Aug 2011 Posts: 32 | I have been gathering parts, some new and some old, in preparation of putting two one barrel Rochesters on my 235.
I have purchased a new Offy intake and my present Carb's base fits the intake perfectly, however, the one that I just purchased off of Ebay looks "exactly the same on the outside but the mounting holes at the base are 2 13/16" instead of 3".
Does anyone have any experience or suggestions as to how to solve this problem?
Always respectful and appreciative,
OUP
"when I grow up - please go ahead and dig my grave!"
| | | | | Joined: Feb 2000 Posts: 5,210 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 5,210 | Are the carb numbers the same? If not, keep looking! You need them to match, not just look the same. There are hundreds of different carbs that all look the same, yet each one has a slight different fuel curve. With a dual set up, each one must match internally as well as externally, other wise half the engine will run different.
This is why carb number (tags) are so important.
When I was hunting down Mono-jets, I found in the early '70s, Pontiac, Buick, Olds, and Chevy all used a single barrel Mono-jet on a 250 (Chevrolet engine), yet each company jetted it differently using different metering rods with different jets. They each had there own idea on what ran the best, on the same basic engine.
Joe
Last edited by Joe H; 10/27/2011 3:30 PM.
| | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | The smaller base is from a 216 & the larger is 235. The model B carbs are pretty simple. I think if you match up the main metering jet they will be well matched. There might be variations in the power valve spring but I dought if it will effect it any.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Aug 2011 Posts: 32 New Guy | | New Guy Joined: Aug 2011 Posts: 32 | Thanks, I haven't taken it apart yet but I have ordered a kit like the one on my truck (fingers crossed there). I'll know more when I get into it and I'll post up some numbers then also.
Is there a chance that, if I could find one, maybe I could put a different base on the smaller carb?
Really didn't want to take my old one off and shut down the truck again but it looks like that's the "only" way I'll know for sure, huh?
'ppreciate it Y'all
OUP
"when I grow up - please go ahead and dig my grave!"
| | | | | Joined: Aug 2011 Posts: 32 New Guy | | New Guy Joined: Aug 2011 Posts: 32 | I should never try and measure anything without my glasses, early in the morning and trying to get down the road to the Wiffy's doc's appt. The smaller one measures 2 11/16 and NOT 2 13/16 !
"when I grow up - please go ahead and dig my grave!"
| | | | | Joined: Apr 2011 Posts: 57 Wrench Fetcher | | Wrench Fetcher Joined: Apr 2011 Posts: 57 | The specs indicate the model 'B' is the small base /216. The main jet specs for that 'B' is 51 with a rich option of 52.
good luck with the duals. | | | | | Joined: Jan 2001 Posts: 5,337 'Bolter | | 'Bolter Joined: Jan 2001 Posts: 5,337 | If you check the venture diameter, you will find the 216 carb will be smaller.
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