Author Topic: Crossram manifold  (Read 35772 times)

369

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Re: Crossram manifold
« Reply #60 on: January 26, 2018, 05:48:11 AM »
Ouch!

Kelley W King

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Re: Crossram manifold
« Reply #61 on: January 26, 2018, 04:51:34 PM »
For 85K I think I will let you guys move on this one. Odd they were in a rush to get it done for a race but the carbs were not made until about 14 weeks later.
69 Z28 RS Scuncio Hi Performance
69 SS L78
67 SS Chevelle
64 Corvette
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WorkinProgress

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Re: Crossram manifold
« Reply #62 on: January 26, 2018, 05:18:26 PM »
Crossram ad says it was being prepared for a 1968 Sebring race. I would think the matched 824 carb dates are fine. Race date was March 23, 1968.
                                                  - Warren

http://www.ultimateracinghistory.com/race.php?raceid=6122

maroman

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Re: Crossram manifold
« Reply #63 on: January 26, 2018, 05:39:12 PM »
Jon, does it come attached to your Z? If so I the check is in the mail.
Doug  '67 RS/SS 396 auto I know the car since new

PHAT69AMX

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Re: Crossram manifold
« Reply #64 on: September 27, 2018, 10:23:41 PM »
Greetings JON MELLO and others,

Greatly appreciate and RESPECT all your work documenting.

New to the forum, found while researching 1969 Hurst AMX S/S cars.

If I may, on your CRG CrossRam & Carb pages, it appears
there may be a couple typo errors on Holley Carburetor Numbers ?

In the body of the text and in the Carburetor Usage Chart.

imho, ? should the 1968 Carburetor Usage Chart should read ?:

302/290 (2X4) 3906631 (proto) Holley # 3810
302/290 (2X4) 3941140 (early) Holley # 4210
302/290 (2X4) 3957859 (later) Holley # 4295

"It appears" the GM #3942595 302 CrossRam FUEL PIPE Number got typed
in error as the GM Part Number for the Holley List #4210 1st Design Carb,
whereas GM #3941140 appears correct for the Holley #4210 1st Design Carb,
and for GM #3957859 appears correct for the Holley #4295 2nd Design Carb.

Appears GM #3906631 is the correct number for the Holley #3810
which was used as a Proto-Type and starting point for the
Holley List #4210 1st Design Carb used on the CrossRam.

There are prototype CrossRam & Carbs pictures on the web
where the Carb Choke Horn List Number "4210" is ETCHED in place,
maybe "3810" is etched out, and GM #3906631 is left as-stamped.

Also, it appears that ONLY the GM and Offenhauser SBC CrossRam Intakes
were made with the "Central Aft Carb BellCrank Relief Pocket"
which allows the Driver's Side Carb to be mounted "Backwards"
allowing for "improved Fuel Air Distribution"...

Whereas the Edelbrock SBC CrossRam Intake,
as well as the Edelbrock CrossRam for the AMC V8's,
does NOT have the "Central Aft Carb BellCrank Relief Pocket"
which "dis-allows" the Driver's Side "Backwards" Carb mounting. 

May be worth mentioning another "unique" feature of the 4210 & 4295
Chevy CrossRam Holley Carbs are their "Left Handed" Center Hung
Fuel Bowl Inlets, combined with the "Backwards" Driver's Side mounting,
allows all the Linkage and Fuel Lines to be centrally located... "clean".

Also, as best as I've been able to establish, it appears that
the SBC 302 CrossRam 2nd Design Holley List 4295 Carburetors
were the 1st Holley DOUBLE PUMPER CARBS ! ? !


Not only was the Edelbrock AMC CrossRam Intake used on the 1969
Hurst AMX S/S 390 "handicapped" with "non-symmetrical" Carb mounting,
it is my belief that the OEM Holley List # 4584 Carburetors specified
were "re-numbered, re-applied, Chevy 302 throwback" List 4210 Carbs.

Nothing but the upmost respect for your work.
Only trying to learn and understand and clarify.

Thank You, C. Kevin Thomas

  CrossRams page:   http://www.camaros.org/crossram.shtml
Carburetors page:   http://www.camaros.org/carb.shtml
« Last Edit: September 27, 2018, 11:49:52 PM by PHAT69AMX »

PHAT69AMX

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Re: Crossram manifold
« Reply #65 on: September 30, 2018, 12:45:03 AM »
Rounded up some images of what is stamped on some Holley Carburetor Choke Towers.
Interesting to see ETCHED numbers on early versions of both the List 4210 and List 4584.
Holley seemed to be fast and furious with innovations during that 1965 to 1969 time period.
The 1965 Z-16 Chevelle List 3310 and other '65 Chevys had
the 1st Dual Line Center Inlet Fuel Bowls
as far as I can tell with research done to this point.

May I ask, does anyone have, would someone post, clear pictures of
an original un-restored Holley List 4210 Stamped Carb Choke Tower, and
an original un-restored Holley List 4295 Stamped Carb Choke Tower with a 1968 Date Code ?

Another subtle difference between List 4210 and List 4295 Holley Carburetors was
both had Roller and Slot BellCranks, but the List 4210 had a "constant radius" Slot,
where the List 4295 had a "W" shaped Slot, so 1:1 4210 versus Progressive 4295 ?


BRG Z28

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Re: Crossram manifold
« Reply #66 on: October 01, 2018, 11:38:02 AM »
When did the switch take place from 4210 to 4295? I have a 7/68 4210

PHAT69AMX

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Re: Crossram manifold
« Reply #67 on: October 01, 2018, 05:59:56 PM »
Using GMPartsWiki, there is a GM Catalog that says it is from October 1968 at the top of the pages
but on the bottom left of the pages it says Rev. 7-1-69... so less than "definitive"... but...
it does list BOTH the 4210 (1st Design) and the 4295 (2nd Design) CrossRam Carburetors...
So maybe by at least Sep-Oct 1968 the 4295 Carburetors were "in the system"... ?
It would be nice to know for sure just when the 4295 Carburetors where phased in,
and guess the GM change to 4295's is what makes 4210 Carburetors so rare maybe.

http://www.gmpartswiki.com/getpage?pageid=218307

Jon Mello

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Re: Crossram manifold
« Reply #68 on: October 03, 2018, 01:51:42 AM »
I don't think you're ever going to find a "hard" date for when the 4295 replaced the 4210 carb but it would have been sometime during the summer months of '68.

I don't have a collection of photos showing 4210 and 4295 choke tower numbers so I personally can't help with that but maybe someone else here can. Some of the pictures above show numbers altered with an electric engraver. I would not call that etched, and there is no telling who altered those numbers. Maybe I'm wrong but that does not seem like something Holley would have done.

You are correct that there is an error with the '68 cross ram carb listing for '68 on our carburetor page and I will get that fixed when an opportunity presents itself. The 3810 is thought to have been a developmental carburetor while the manifold was undergoing initial development.  There would not have been a cross ram unit that left GM for public consumption with a pair of these 3810 carbs on it, in my opinion.

The '68 cross ram carbs should read...
302/290 (2X4) 3941140 (early) Holley # 4210
302/290 (2X4) 3957859 (later) Holley # 4295

You're also right about the 3942595 part number being incorrectly types for the carburetor when it was one of the fuel pipes so that is another thing for me to fix. I appreciate your help so that I can put correct information out there.

I don't believe the 4295 is the first Holley double pumper as I remember talking with GM engineer Bill Howell (part of Vince Piggins' Product Promotion Group) and he told me years ago that he was testing an 800 double pumper carb on the Penske Camaro right after the '67 Trans-Am season finished. This was before the cross ram was available and was in the Oct-Nov 1967 timeframe.  I just asked him again a couple of days ago about cross ram carburetors and double pumpers and here is his reply..."As a test engineer in the lab, I had no release responsibilities, so I did not keep track of part numbers and minor differences in many new parts being considered for release.  By the time the 2x4 package was released for production, I was in Vince's group, so I had limited interest in those details.  I knew the carbs were 600 cfm, and their double pumper characteristics.  In their production layout, they were difficult to work with, so we reversed end for end the float bowls to get the fuel fittings outboard.  This also increased the difficulty in setting the fuel levels, as in production, they were different front to rear. I would have to adjust the fuel to the bottom of the sight plug, and then raise or lower it to the correct recommended level after reinstalling the sight plugs.  Your recollection that the Marlboro test in 1967 probably involved a double pumper 800 cfm is correct in my memory (tho I have no written record for reference).  It amazes me how accurate my memory of the 1960's is compared to the 1980's.  I guess that speaks to the level of excitement I was experiencing during those times.  I hope the above information is of benefit for your research."
Jon Mello
CRG

PHAT69AMX

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Re: Crossram manifold
« Reply #69 on: October 20, 2018, 06:18:19 PM »
Agree that the "Engraver" marked carbs look something other than "legitimate"...
but when I saw pics of early claimed original Hurst S/S AMX CrossRam 4584 Carbs
and pictures of early claimed original Chevrolet 302 CrossRam 4210 Carbs both marked the
same way with an Engraver it made me wonder if that's what Holley may have done in '68.
At least on very early "needed now for sanctioned racing teams" at the beginning of the season where
the winter off-season R&D ran a little long leaving little time for "production versions" of those carbs.

Wonder if the 800 Double Pumper was a one-off 302 CR "R&D" Carb not produced and sold?
Or maybe if they were a pair of the short-lived Holley List 4223 850 cfm Center Squirter Carbs?

Find it very interesting where one can see the progression in the 3 carbs used on the 302 CR,
from Single Line Vac Sec, to Dual Line Center Hung Mech Sec Single Squirter, to Dual Line Double Pumper.

It's just a curiosity, specifics of 3 Holley 1st...

Holley List 1272 = ? 1st Modular Model 4150, 1957 ? debuted on a Ford
Holley List 1850 = ? 1st 600 cfm Vac Sec Modular Model 4150, also 1957 ? Ford 312
Holley List 3310 = ? 1st Holley Dual Line, 1965 Z-16 ( one of a few List #'s debuted on Chevy's in '65 )
Holley List 4295 = ? 1st Holley Double Pumper, 1968 302 CrossRam

Surprised have been unable to find those Holley "firsts" already specifically documented...
Amazed two of them are still going strong as the most popular Universal Carbs, the 1850 & 3310...

Jon Mello

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Re: Crossram manifold
« Reply #70 on: October 24, 2018, 03:13:25 AM »
Might be worth talking to somebody at Holley for their opinion on the engraver markings but with this many years gone by, nobody there might be "in the know".
Jon Mello
CRG

PHAT69AMX

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Re: Crossram manifold
« Reply #71 on: October 25, 2018, 08:43:47 PM »
Past Holley contact attempts failed to turn up knowledgeable "old timers".
They "sent me" to Holman-Moody and Daytona Performance for "History" questions.

Interesting, in practice Bill Howell says they reversed the
production Cross Ram Carbs Fuel Bowls for outboard Fuel Lines
making Float Level setting more "complex" but the overall set-up
easier to work with than production "compact all central" layout.

Seems maybe Holley Center Squirter Carbs were developed prior to
Double Pumpers, "implied" by possibly a numerical order application
of Holley Carburetor List Numbers...
List 4223 being an 850? Center Squirter & List 4224 being a 660,
whereas the later Cross Ram Double Pumper Carbs are Holley List 4295.

Came across a post of yours in the "Traco Fans" thread, page 11, post 160,
with a pic of Bill Howell & Mark Donohue at Marlboro Raceway testing tires
and "the new Holley Double Pumper Carb", after the '67 TA Season,
maybe in Dec '67, as mentioned in your previous reply posted here.
From it I see where my previous post incorrectly asks about possibly a "pair"
of Center Squirters being tested then, when it was a single Carb Intake Test.

Any chance maybe the ~Dec '67 Single Carb Marborol Test was a Center Squirter ?

BRG Z28

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Re: Crossram manifold
« Reply #72 on: October 25, 2018, 09:14:39 PM »
Most of the 4210 I have seen, the air horn have been drilled for center squirters. I assume this was never done by Holley.... Were the center squirters a Holley acceccery? If not who made the Holley center squirters?

PHAT69AMX

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Re: Crossram manifold
« Reply #73 on: October 25, 2018, 11:16:32 PM »
Yes, have seen "modified" List 4210 Holley Single Squirter Mechanical Secondary Carbs
with aftermarket "custom" Squirters with extra "tubes" that reach back to the secondary side.
see pics ( one modified 4210 pic i think is from elsewhere in this thread iirc ),last pic is a 4223 850 Ctr Squirter

Due a Google Search for Holley 4224, it's still made and available as I understand, it is a 660 CFM Center Squirter.  The 850 CFM Holley List 4223 lasted only 1 or 2 years and was then discontinued.  Can also google search it for pictures.  They have a single 4-Tube Center Mounted Pump Shooter that is located where the Air Cleaner Stud usually screw in, then there is a separate "special crossover" Air Cleaner Stud "Plate" that mounts across over top of the single 4-Tube central Squirter that sprays into all 4 Throttle Bores at once.  The Linkage is somewhat unique for the Center Squirters, the butterflies open almost 1:1 AND both Pri and Sec pivot "inward" towards each other, unlike "standard" Holley Double Pumpers.  Pretty sure the 302 Cross Ram Holley List 4295 585 CFM Double Pumpers also have the unique "towards each other" butterfly Pivot configuration but are "staged" or "progressive" rather than 1:1, but are true Double Pumpers where the Center Squirters are "Single Pumpers" but have the single centrally mounted 4 Discharge Tubes and squirt into all 4 Venturis at the same time and uses the 50cc Pump iirc.

PHAT69AMX

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Re: Crossram manifold
« Reply #74 on: October 25, 2018, 11:20:47 PM »
Or are you speaking of a 4210 modified like this pic I may have saved from earlier in this thread ?
Second vintage pic is a pair of List 4224 660 Center Squirters on an AMC Cross Ram.