Same Rochesters but different mounting holes

[wretched ratchet]

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,
WR

 

[dmw56]

If you are taking about the carbs the smaller one is for a 216 engine. They can be made to fit by just filing the mounting holes to fit. However, I would recommend finding matching carbs.

 

[wretched ratchet]

Thanks, I made a mistake in measuring the holes early this morning, without my glasses and trying to get the Wiffy to her doc's appt. It is 2 11/16" instead of 2 13/16".[S

 

[brokenhead]

the small base was for a 216, and the large base was for a 235, many of the old timers suggest using 2 of the small bore carbs otherwise you get too much carburetor. (they are actually different CFM as well) Some have suggested bottoming out studs in the holes, cutting/milling them off flush and redrilling the holes, but being an aluminum manifold I am not sure how that would work, unless you make up some aluminum studs, which is entirely possible. Keep in mind these (rochesters) will be absolutely miserable to tune and to keep tuned. But thousands of people have done it. And most of them I have spoken to didn't really care for it.

 

[klink]

Either size carb works well just make sure they are the same. The spread difference is only 1/8". If you use the 216 carb I would recommend opening the holes the 1/16 per side, don't mess with the intake. I think you'll find syncing the carbs will be easier than most people think, just make sure your intake has a heat source.