Author Topic: TRACO Fans  (Read 110245 times)

Coloradoamx

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Re: TRACO Fans
« Reply #195 on: November 15, 2018, 02:27:58 AM »
I finally took the plunge and relocated the dry sump tank to it's proper place.  I had it mounted inside the car, but the original SCCA rules required that it was to be "forward of the firewall."  This is the place the original Penske car had had the tank located. 



Jon Mello

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Re: TRACO Fans
« Reply #198 on: November 21, 2018, 01:23:44 AM »
Thanks for posting.  Those are really neat.
Jon Mello
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PHAT69AMX

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Re: TRACO Fans
« Reply #199 on: July 07, 2019, 07:31:02 PM »
Hope not to "junk up" this thread, but it is where Jon Mello graciously posted on
page 9, reply #131, pictures of a brand new Holley List 4830 GM 3965736 Double Pumper Carburetor.

I am not sure, but from research have come up with a theory why the 4830 "exists".
In most basic terms Holley Carburetors are "grouped" or "sized" by Throttle Valve ( Butterfly ) Diameters.
1-9/16" Dia, 1-11/16" Dia, & 1-3/4" Dia, are the 3 "Basic" Square Flange Performance Carb "families".
GM / Chevrolet 1st had Holley Double Pumper Carbs with 1-9/16" & 1-3/4" Throttle Valves
and this left a "vacancy" at the 1-11/16" Diameter Double Pumper Level, which the List 4830 filled.
That's my theory / "discovery", what I wanted to share for your review, comment(s).
Information found in the 1971 GM Chevrolet Special Equipment Catalog fueled (ha!) this opinion.

At the top of catalog page 8 is a brief Carburetor "Summary Chart" showing 3 Double Pumper Carbs:

1-9/16" Dia. 585-600 CFM Double Pumper List 4295 # 3957859 - '68 Xram 2nd Design
1-11/16" Dia. 830 CFM Double Pumper List 4830  # 3965736 - ? not used as OEM ?
1-3/4" Dia. 850 CFM Double Pumper List 4296 # 3955205 - L88 & ZL-1

As previously posted elsewhere, in the Trans Am Camaro Section, research and conversations
suggest that the very 1st Double Pumper Holley was the 2nd Design 302 List 4295 585 CFM DP
and / or, or maybe at the same time, the L88 2nd Design List 4296 850 CFM DP.
Then the List 4830 830 CFM DP was procured / produced to "fill the 1-11/16" Gap"...

GM and Chevrolet appear to have been 1st to conceive, procure, and use Double Pumpers in late '67 & '68.

The "universal" Series of Holley Double Pumper Carburetors from 600 to 850 CFM we all know as the
4776, 4777, 4778, 4779, 4780, 4781 were introduced in 1969 per a '69 Shelby Catalog, AFTER the GM ones !

The "mid-sized" List 4830 1-11/16" Dia Throttle Plate is used in ALL of those, except the smallest and largest.
And the smallest, 1-9/16" 600 4295, and the largest, 1-3/4" 850 4296, Chevy developed and had 1st !

Interested in others opinions, if any, Thank You.