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Rochester HV carb mods - WTH is this???
Posted by: rbeard2300 ()
Date: February 17, 2020 08:46AM

Hi all,
First time long time. In assembling parts for my new 66 Monza 140PG project, I happened upon a great deal on ebay for " Vintage Rochester Gm Carb Carburetor (for parts) Lot" which upon further inspection revealed 5 H/HV carbs which i won for $20 plus shipping!
Anyway, after a good cleansing and decoding the tags, the two yellow painted ones are 1963 Corvair HVs with a modification to the tops I have never seen before: It looks like red epoxy has been dabbed onto both sides of an air bleed orifice? (see pics) I suspect these two 1963 primaries may have been converted to secondaries for a 4 carb 140HP motor as two of the other carbs in the set were very obviously 1967 primaries of a '67 140. By the way, the 5th carb in the set decoded as a 1969 pontiac?? I guess for parts.

Anywhoooo . . . You guys know why someone would have done this?

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Re: Rochester HV carb mods - WTH is this???
Posted by: MattNall ()
Date: February 17, 2020 10:46AM

Welcome to the CCF!


Looks like someone opened up the area for a larger washer? Crude... but doesn't hurt!

Sadly those are Bale tops...not used on a 65 unless it had AC!

note... When scanning pics.... do a "Preview" and move the scanbox to just the photos or areas you want to show.

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Rochester HV carb mods - WTH is this???
Posted by: RexJohnson ()
Date: February 17, 2020 10:48AM

The place that is circled in red is where the "J" hook on the later air cleaner systems hook into. On earlier carbs that used the wire hold down (like a brake MC) that part of the carb is hollow. So if those are early carb tops and someone drilled that area to use a later air cleaner system they also added a bowl vent. The carb tops can be switched around on some years of carbs. The problem with that vent is that it also lets water and dirt in to the float bowl. So someone later must have figured out this problem (maybe after washing their engine) and the holes were sealed up. After all of these years going by the tags only is not the best way to identify them as tags have been moved around, you don't know where they started from. Bob Helt wrote a great book with a lot of pictures to learn about these carbs and to help identify what you have. Seth Emerson now carries Bob's books. An example of the tags being moved around is that none of the 5 carbs look like they came off of a Pontiac, but all look like from a Corvair.

RJ tools
Salem,Oregon

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Re: Rochester HV carb mods - WTH is this???
Posted by: FLSteve ()
Date: February 17, 2020 12:40PM

They all look to be early carbs.

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Re: Rochester HV carb mods - WTH is this???
Posted by: PGVair ()
Date: February 17, 2020 02:45PM

Without looking in Bob Helt's book, since theses carbs have the two vent holes beside the choke butterflies, they could be LM carbs that someone added the bail holes for flat air cleaners and plugged the holes for the j-hook air cleaner hold down fasteners.

Wade

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Re: Rochester HV carb mods - WTH is this???
Posted by: American Mel ()
Date: February 17, 2020 03:17PM

PGVair Wrote:
-------------------------------------------------------
> Without looking in Bob Helt's book, since theses carbs have the two vent holes beside the choke butterflies, they could be LM carbs that someone added the bail holes for flat air cleaners and plugged the holes for the j-hook air cleaner hold down fasteners.
>
> Wade


I have a stack of LM carbs in my mud-room right now, and all of them have j-bolt holes, AND the bale-holes.

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
Have; '66 Monza Coupe - 140, 4-spd. Daily driver beater
'67 Monza Vert. - 140, 4-spd. Daily driver beater
'67 A/C Moredoor Monza
Have had; '61 Monza coupe, '62 Monza Wagon, '63 Spyder, '65 Corsa
.
non-vair
'04 Dodge Cummins Quad Dualy, approaching 400K
17'Terry



Edited 1 time(s). Last edit at 02/17/2020 03:20PM by American Mel.

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Re: Rochester HV carb mods - WTH is this???
Posted by: American Mel ()
Date: February 17, 2020 03:18PM

MattNall Wrote:
-------------------------------------------------------
> Welcome to the CCF!
>
>
> Looks like someone opened up the area for a larger washer? Crude... but doesn't hurt!
>
> Sadly those are Bale tops...not used on a 65 unless it had AC!
>
> note... When scanning pics.... do a "Preview" and move the scanbox to just the photos or areas you want to show.


Whatza matter Matt?
You offended by Metalic Pink Fingernails? grinning smiley

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border,
I am not at the end of the world, but you can see it from here.
Have; '66 Monza Coupe - 140, 4-spd. Daily driver beater
'67 Monza Vert. - 140, 4-spd. Daily driver beater
'67 A/C Moredoor Monza
Have had; '61 Monza coupe, '62 Monza Wagon, '63 Spyder, '65 Corsa
.
non-vair
'04 Dodge Cummins Quad Dualy, approaching 400K
17'Terry



Edited 1 time(s). Last edit at 02/17/2020 03:20PM by American Mel.

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Re: Rochester HV carb mods - WTH is this???
Posted by: PGVair ()
Date: February 17, 2020 07:04PM

Earlier carbs did not have the two vent holes as these carbs do, but instead one vent hole down in the duckbill.

Wade

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Re: Rochester HV carb mods - WTH is this???
Posted by: Frank DuVal ()
Date: February 17, 2020 08:11PM

Wade is correct.

Frank DuVal

Fredericksburg, VA

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Re: Rochester HV carb mods - WTH is this???
Posted by: PGVair ()
Date: February 18, 2020 09:10AM

Ok, I looked in Bob Helt's book instead of trying to go from memory. The two vents on the sides of the airhorn were added in 1963 in addition to the duckbill vent. In 1964 the duckbill vent was eliminated and the two airhorn vents were enlarged. Also in 1964 the j-bolt hole was added into the existing web for the new style air cleaner. I can't tell from the pictures if these carbs have the duckbill vent or not.

From looking at my spare carbs, when the j-bolt anchor holes were added the web was filled underneath the carb top cover. Prior to the j-bolt carbs, the web was hollow, so if a hole was drilled through the hollow web, it would allow an open path for dirt to get in the carb.

It would help if we could see a picture of both sides of the carbs aligned with the throttle shafts. In 1964 the base vent was added below the side with the idle screw and in 1965 the power enrichment system was added. On the side opposite of idle screw side, the PES carbs have a raised section running vertically on the outside of the bowl and a lead plug at the bottom of that raised section.

Wade

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Re: Rochester HV carb mods - WTH is this???
Posted by: rbeard2300 ()
Date: February 18, 2020 12:12PM

Thanks so much all!! I'm at work now but will definitely pull some numbers off the carb bodies and shoot some more pics to post. 4 of the carbs seem easily rebuildable (after several hours in my homemade sonic parts washer) and I would like to keep them around for spares and jet swaps with the 4 factory carbs on my '66. BTW, that is not my finger in the pic above! You can tell because I would never wear "metallic pink" nail polish! I'm much more of a "Kandy Apple Red" guy!

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Re: Rochester HV carb mods - WTH is this???
Posted by: joelsplace ()
Date: February 18, 2020 04:10PM

Since you don't have a signature we wouldn't know. Some of the members here are girls.

Joel
Northlake, TX
5 Ultravans, 114 Corvairs and counting...

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