Road Runner Nest

Hi everyone.

For a while now I've ponder the idea of a six barrel setup for my 440 engine, and right now I'm researching the oe casting numbers for 71 center and outboard Holleys. What are those numbers?

I believe I have the outboard carb's number at 3462373? Is this correct? I've also seen the letters MTX associated with the 71 carbs? What does that mean?

Did they make any chances from the 69-70 version carbs, besides casting numbers? Did early built 71 cars come through with the prior year castings, including the aluminum Edelbrock intake?

Just curious to know if Ma Mopar put any out before the switch to iron.

Thanks a million!

The original 440+6 intake for my car has a casting date of almost a year before the scheduled build date of the car.....and it's an iron intake. I believe iron intakes were used on most if not all 70 cars as well. If I remember correctly, mopar switched to iron cast in their own foundaries because there was a supply issue with Edelbrock. Casting # for the iron intake is 2946276
Carb numbers...depends if it's an auto or 4spd. Part #s:

auto center - R4670
4spd center - R4669
front - R4671
rear - R4672

as usual, Eric is the numbers man.

I see you are from eastern PA,what town?

I just read an interview with Vic Edelbrock Jr. in the current edition of Muscle Car Review about the 69 ½ Edelbrock 440 six-pack manifold. In that article he claims the switch to the in-house produced cast iron six-pack manifold in model year 1970 was an economic decision on Chrysler’s part and not a supply issue with Edelbrock.
IMO, with Edelbrock continuing to produce this manifold today, having a rather hefty weight savings over the cast iron piece and a cost of what, $325, short of a full-on numbers matching concours correct restoration, why would you not go with the Edelbrock manifold?

Eric, I appreciate that information. I realize I forgot that Chrysler made the switch in 1970. Interesting information from Vic Edelbrock Jr. The story I have always seen published is the short supply of the alumiunm intake.

mopar71, I live in Sullivan County, between the towns of Laporte and Dushore, right along Route 22. I'm up here in the mountains. Nice and rural up here, with plenty of open roads to enjoy the bird and only a single traffic light in the small down of Dushore; next furthest traffic light is a good 45 minutes away. I take it your close to Route 6, up by Scranton? How is it there?

Anyhow, now that I have that knowledge, who offers a complete Six Barrel kit? The one I have found through eBay is from Atlantic Speed Performance Parts. What they offer is the 69-70 Holley reproductions with the early casting numbers and correct Edelbrock intake. Do you know any one that offers a kit with the 71 casting Holley's? This is for an automatic car.

Actually this is going to top my current 440 stroker. I'm going with a nostalgia, period look with the engine and deiced to go with the Six Barrel, which will be tuned. I believe it's Quick Fuel that offers the metering plates with the removable jets. I'm trying to find all sorts of help for this engine to make her just right and last, however, since traffic flows fast through moparts, I would ask the fellow 71-74 Mopar pentastars my questions for any luck.


Forget to add the link to the six bbl kit on Ebay from Atlantic Speed...

Six Barrel Kit


Thanks again,

Adam

When I was looking for carbs for my RR, I learned that Holley does not make the 71 castings any longer. Apparently they used to but stopped a little over a year ago. I do see them on Ebay once in a while from distributors who have some in inventory. Now someone told me, and please verify for yourself, that the new ones Holley makes is actually based on the 71 carb but has the 70 cast numbers on them. Again I have not verified this. Something to do with the bowl vent I think.

In 71’ the bowl vent on the center carb was enclosed and fitted with a 3/8” hose nipple. Pre 71’ bowl vent consists of a small rubber plug over a hole in the top of the bowl. On a 71’ this hose was connected to the breather cap. The purpose was to burn the bowl vent fumes through the PCV via the crankcase rather than vent to the atmosphere. Beginning in 72’ a carb bowl vent line would connect to the charcoal canister and then metered back through the PCV line.

72RoadRunnerGTX wrote:In 71’ the bowl vent on the center carb was enclosed and fitted with a 3/8” hose nipple. Pre 71’ bowl vent consists of a small rubber plug over a hole in the top of the bowl. On a 71’ this hose was connected to the breather cap. The purpose was to burn the bowl vent fumes through the PCV via the crankcase rather than vent to the atmosphere. Beginning in 72’ a carb bowl vent line would connect to the charcoal canister and then metered back through the PCV line.

You mean the 3 nipple 71 valve cover breather?

Yes, the third nipple connects to the fuel tank vapor separator. Again starting in 72’ the tank vapor separator line was routed to the charcoal canister.

Look at Ebay item number 360079609481

Description says OEM 71 Hooley NS1 carbs.

But they don't give out the list numbers

The carbs I have came from MP under the numbers P4349237 (center) and P4349238 (outboards). Checking today they are still being offered on the website. Summit racing has them under the number DCC-4349237 and DCC-4349238. It is my understanding that these are new Holley reissues of the original carbs. One easy way to tell the difference between NOS or original carbs and more current reissues is the presence of hex headed bowl screws. Original/older Holley’s would have slot headed bowl screws. I will have to double check, but I do believe they are stamped with the correct 71” list numbers.

Not sure if this would help but someone posted this site awhile ago.You can find part numbers and such.

http://www.lightningjar.com/mopar/

It's all pretty confusing. I checked out Summit Racing, and they list different o.e. casting numbers for the 1971 holley carbs that Eric listed above, in addition, they only list the center carb for a manual transmission, however, they offer the outboard carbs for either a manual or automatic.

general, I sent the seller a question regarding the numbers and I'm waiting on his response.

I also noticed that in the pictures Summit supplies on the holley carbs, they show slotted fuel bowl screws or could I be looking in the wrong spot? Just trying to understand more about the changes between nos and current.

I thought it would be neat to have 71 casting numbers, or heck, o.e.m carbs to go with the engine; though on the pricey side, or go ahead and purchase a reissue kit for less for close to the same effect. I'm not a numbers match fan, though I do like to know the differences of what the factory did and the after market supplies.

Thanks for the help,

Adam

IMO,
There was a time many years ago, when others my age would have been studying for college, I spent countless hours thumbing through 3 inch thick Holley parts catalogs trying to determine the variances in different Holley list numbered carbs. Here’s a bit of what I learned. First Holley carb numbers were stamped (not cast) into the main body of the carb, and are referred to as “list” numbers. A Holley carb is biased on the numbered series of similar design; six-pack carbs are of the 2300 series Holleys. Holley six-pack O.E. list numbers represent a specific designed configuration of the 2300 for a narrow application. Back then all O.E. carb tuning was performed by Holley at manufacture. Idle mixtures were set using flow meters and in the case of the outboards, mixture screws were then sealed with lead plugs. The center carbs were set up the same way and then had a limiting cap fitted to mixture screws to prevent adjustment in the field. The metering plates on the outboards were not the same from front to rear (slightly different main jetting), different list numbers. Automatic trans cars (ATX) would have had a slightly different idle mixture than a Manual trans car (MTX) and would have a list number for each appication. This insured that they could bolt them on at the factory without fussing with tuning and prevented easy tampering buy owners and others. As long as there were no changes to the stock engine configuration and it remained in perfect tune there shouldn’t be a need to adjust the carbs. This also meant that during the one year warranty period, techs in the dealer network could replace a faulty carb with a corresponding list numbered carb pretty much bolt off—bolt on, again not wanting to payout for any tuning time. Yearly changes to the carbs meant a new set of list numbers.

So, of course every Holley O.E. list number has to have a corresponding Chrysler part number. You can find tables for them most anywhere. When a Chrysler part becomes obsolete or is no longer serviced by Chrysler the part number is referred to as NS1. Back then the only way to get these carbs new was through a dealer using a Chrysler part number, now long since NS1. Holley never sold O.E. list numbered carbs directly in the past.

Jump ahead to present day, with resurgence of the muscle car restoration hobby the last decade or so, Holley has reissued some of the six-pack list numbers. Basically a set of carbs for the small block and a set for the big block application. The big block carbs are updated versions of the 71’ R4670 (center) and R4672 (both outboards). These carbs have new Chrysler “P” part numbers and can be purchased from MP or indirectly from third party sources. Holley's web site currently offers reissue carbs with what appear to be 70’ list numbers (4144 & 4365 outboard). I recall that MP used to offer a big block 69-70’ set along with the 71’ carbs. I wonder if maybe MP and Holley spilt up the marketing of these carb sets. One of the few changes Holley has made to most their carbs was moving to a hex headed bowl screw. As most of us know fuel bowl screw torque is most important on a Holley and the old slotted screws were not easy to torque correctly. You can buy a kit containing the old screws to retrofit a newer carb. Metering block/ Fuel bowl gaskets and power valves are of current design.
BTW, these carbs do not have the idle mixture screws covered or blocked.

Summit's picture showing the hex headed bowl screws.

Service Manul shot of slotted bowl screws

Thanks for the good info,I remember looking at the old holley books and rebuilding the carbs,MAN, if I could turn back the hands of time!