Technical carb question, HOLLEY LIST 4737-2, can't find info...

This carb...is driving me batty.

It's a double pumper from an engine I sold a fellow a few years back, it was on a SBC, and it ran pretty well, but I cannot find information about this specific LIST number? I found a couple that were close, MoPar stuff...but nothing telling me what I need to know, CFM, etc...

...anyone got any of the old books that reveal anything about this chunk o' aluminum? Is it worth messing with or is it ballast?

 

1970 383 automatic.
Chrysler PN - 3512965

 

I Googled it and got 1970-72 Mopar as well..you sure it's a double pumper? Pics that show up in relation to that search show a regular looking 600 CFM or thereabouts vacuum secondary carb...

 

On the HAMB, double pumper means the gas goes into both float bowls...Its sort of like the meaning of "gasser" or "traditional hot rod" on here.

 

Cmon George...lol

 

4737 used on early 70's Mopars is a Carter AVS.

If you go to Holley's own numerical listing of their carbs at http://documents.holley.com/techlibrary_carb_numerical_listing.pdf there is no 4737.

Nearest thing would be a 4773 which is a 450 cfm model with governor used on 427 Chev truck engines.

 

I looked for that List number in the books I have and didn't find it but a Google search showed something I never knew. The 4737 Holley is for a Chrysler 383 335 horse engine, with the optional air cleaner, fresh air hood and auto trans. The interesting part is the secondaries are quite a bit larger than the primaries, not just a little, but by quite a bit. It has bowls with nonadjustable needles and seats, a different location for the curb idle screw, but otherwise it pretty much looks like a typical 4160 style Holley. With the big secondaries it has to use a specific throttle body to main body gasket and who knows what else.
The reason for the bigger secondaries was for the fresh air hood, but I found no CFM info.
As metlmunchr posted above there was a Carter AVS oddly using the same number, but with an S added- 4737-S

 

Sure enough the 4737 Holley shows up in this Holley document http://documents.holley.com/199r10015-1rev1.pdf Once again, no CFM or bore sizes here either.

Shows it as a 4160 type as Fordors said. Strange thing is, glancing thru the carb numbers in this one, I didn't see any of the common numbers like 1850 or 3310 or 4780.

 

nope...I've been around long enough to know a double pumper has two accelerator pumps, as this thing does...and it's not a spreadbore like a quadrajet or thermoquad, or the Holley spreadbore replacement.


Trying to get photos, but my cell phone died...I'm good with mechanical things, this tech crap is best left to the kiddies.

 

As mentioned it has larger secondaries, but we made no mention of it being a spread bore like the Holley 4165 series carbs.
Get help to post pictures if need be, I'd like to see this thing.

 

Welcome to the wacky, sarcastic, but oh so correct world of falcongeorge

 

Senior Mrs. Falcon:
"Are you doing your homework, George?"

George:
"Sure as shootin', Mom..."

 

I will try to get photos, but I'm afraid y'all will be disappointed.

I'm sitting here embarrassed of myself...it's not an uncommon carb at all, upon closer inspection it just so happens that someone tried to make the second "7" look like a "3," for what reason I can't figure...unless some creep tried to pass it off as a MoPar replacement? LoL...sorry for the unnecessary use of bandwidth here...

...I guess it's just a plain-jane 650 cfm 4150 that has been in the possession of an unscrupulous owner in the past

Should be decent on the .040 over 350 since I'm doing more driving than racing, with only an occasional display of testosterone via my right foot.

 

Holley made some specific carbs for oddball applications such as the double pumper I have that came off an International truck with a governor. These do not show up on most lists, but an e-mail to Holley
will usually get you a response within a couple of days showing the original application.

 

Hey, if nothing else we now know there are 4160's out there with really large secondaries. Here are photos from a Mopar restoration 'site.

 

You


Sent from my iPhone using The H.A.M.B. mobile app

 

That's a little strange, boosters are different in the secondaries than the primaries. And I've got a factory Holley for a 70 model 440 on the shelf that's a plain old 600.

Chrysler isn't the only one to use different built Holleys, I have an 830 cfm double pumper with factory Chevrolet numbers that Holley doesn't list in their catalog either. The listings you do find list it as Chevrolet carb for Trans-Am racing.

 

There is a lot more to venturi boosters than I know but I can tell you that the original 3310 was a 4150 style carb and had down leg boosters and a 780 rating. Holley changed it to the 3310-3 (cheapened it up?) for the mass market and made it into a 4160. At the same time the boosters went to straight leg and the rating dropped to 750 CFM. I don't have either carb any longer so I can't say if there was a secondary venturi diameter change at the same time. My point is, does a different booster work better with a particular venturi? Beyond my knowledge for sure, I'm just commenting on things I've seen over the years.

 

About all I know is that the 600s use the booster with the baffle (????) in the center of the booster, most of the larger cfm carbs are open in the center.

It actually looks like the 383 carb uses the primaries of a 600 and the secondaries of a 750/780.

As far as to what works better, I guess it depends on the use of the carb, or they wouldn't make straight/dogleg/annular discharge boosters for the same cfm carbs.

 

ah-ha! NOW it makes sense.

 

Straight leg aka nozzle bar boosters pose a greater flow restriction than downlegs. I switched to Braswell two-step undercut downlegs in a 650 double pumper and picked up about 20 cfm per hole on my bench. That and slabbed throttle shafts got me a 1 1/4 by 1 5/16 venturi carb that flowed close to 800 cfm with the choke horn still on it.

 

Here's another one...it's grimy and will be cleaned up, but a second carb from the pile o' freebies, notice anything amiss?

 

Main body is turned 180, can only imagine what else is screwed up internally.

 

^^^^^ For when you only want a little more secondary action. (spread bore joke. But who's paying attention to detail's ?)

 

yep...I didn't even know that was possible. a teardown and cleaning will tell if a rebuild is going to do any good. might be an interesting paperweight.

 

my facebook version of this post got a comment of "Absolutely nothing. . It's a boat carb.. also used on many circle track cars"

I don't see how...even a boat carb would have the choke over the primaries instead of the secondaries, if running a choke at all? LoL at any rate, my day off and I'm going out to tear it down. Will have to wait for the wife's cell phone to come home with her so I can get decent photos of any craziness I find...

 

What's the list number on the choke horn?

It's not a boat carb, they have vents (kind of j shaped) that dump into the venture if they flood over.

 

It's a LIST-4777-2 like the one I originally mentioned in this post.

I knew it wasn't originally a boat carb, but thought someone might have tried that reconfiguration my friend spoke of, there ARE a lot of wannabe Stroker Aces around here.

I tore it down, doesn't look like anyone drilled anything out or modified anything other than putting the main body backwards and the metering blocks on the wrong ends I got lucky I guess!

As things come together I'll post pics of the blasphemous sbc swap into a 53 Ford Mainline...it'll come back out when I find the "right" FoMoCo befitting of Henry's blue oval, I just wish the old stuff was as readily available as when I first ventured onto the HAMB in '99-2000...

 

You posted 4737-2

 

See post #13.