Question about buying Carter BBD for my 318 (unless I should look at something else)

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67CBodyGuy

67CBodyGuy

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The 318 (on my '67 Monaco) might be in need of a better carb, the only one I've ever known is the Carter BBD. I see them for sale on ebay for relatively cheap, about a hundred bucks, they look nice and new.

So here's my questions. I see lots of Carter BBD's for sale but basically they boil down to 2 carbs. One type is exactly what I have, only one or twp ports, the accelerator pump linkage is visable. The other type has a raised box around the accelerator pump so you really can't see it, and a LOT of ports that I'd have to plug. I'm assuming the carb with a lot of ports is a more recent design? Does it perform better? (Performance, as in getting the air/fuel mixture right, especially when idling, MPG, etc).

My other question, should I ditch the BBD and look at something else? That is still 2 barrel. Something that might give better idle, and the best city/highway MPG possible? If there's nothing that stands out here, then I'm back to question 1 above.

Thanks for any input.
 
I have never seen a carb so worn out that it needed replacing. But-um,
I have seen:
Many a plugged carb-heating system,
many faulty chokes,
and many many Ignition timing systems that needed a buncha work,
Not to forget, the occasional;
faulty cooling system thermostat,
out-of-time cam,
lousy torque convertor,
tight U-joints,
dragging brakes,
over-filled automatics,
and
guys running on tires with not nearly enough air pressure in them.

So I gotta ask why you feel the need to change the carb?
 
67CBodyGuy said:
The other type has a raised box around the accelerator pump so you really can't see it, and a LOT of ports that I'd have to plug. I'm assuming the carb with a lot of ports is a more recent design? Does it perform better? (Performance, as in getting the air/fuel mixture right, especially when idling, MPG, etc).
Click to expand...
Yes and no
The later design is better but-um will likely run too lean on your 67. Some of the extra ports will not be applicable in your application, but could be used to advantage.

But if your 1967/56yearold engine is having an Idle issue, it may or may-not be a carb-issue. I would start with a compression test, a cylinder ballance test, and if those are up to snuff, then an ignition system diagnostic/tune-up
 
The throttle shaft bushings could be worn, causing a vacuum leak. Test it while running with brake clean or WD40.
 
The engine was bought in '87 as a remanufactured crate engine from a chrysler dealership when I was restoring the car (my dad's car). It is an LA engine, the original was a polysphere (Canadian car, which explains why there was a 318 in a C body to begin with). I only put 10k miles on the car after that, and the car has been in storage for the past 25 years. I took it out for the first time last year for a couple weeks, it's out again and I wasn't liking how rough it idled. I think I might have partially solved that by replacing the coil (secondary resistance was measuring 24k ohms when it should be 11k, I had a few old / original coils to compare with and swap).

I've put in new points, condensor, rotor and balast resistor, new plugs (RN14YC). It did have a combination of N and RN 12YC before it was stored. Plug wires are silicone, 500 ohms per foot (so not crazy-high resistance wire nor straight zero-ohm wires either) but they are 20+ years old.

Compression tests, even when done cold, are 150 - 160 PSI after 4 cranks.

Plugs are black / sooty. Best idle vacuum I can get is 17 inches with a 1 inch bounce at 500 rpm. Vacuum goes to 20, maybe 22 when RPM is 1000 - 1400 (engine runs very smoothly at those higher rpm's).

Very very little play in throttle shaft. Choke pull-off works great. The carb air-horn gasket (the gasket between the main carb body and the top air-horn casting) seems to seep a little bit of gasoline when running. I'm wondering if there's too much fuel in the bowl. I've adjusted the idle mixture, I can turn 1 screw completely in and idle is very rough but it does keep running.

I read about the need to clean these various low-speed idle passages and such, the idea of just replacing the carb with a brand new one is growing on me (I didn't know they were so available and so cheap).

I don't think I'll get any further by changing more ignition parts. I did recently buy a new NGK 53420 (RC-CRX010) wire set which also has 500 ohm/ft and a new blue streak dist cap with brass contacts but I want to hold those back for a few years until the car really needs them.

I don't mind running lean if it clears the plugs and I get better milage. Should I buy the newer-style BBD carb with all the ports? Do I just plug the extra ports?
 
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Instead of dealing with 30 to 50 year old parts, get an aluminum intake and a new Edelbrock 635 CFM carburetor. I 99% positive you will NOT see any decrease in fuel economy, I'll bet that it may get even better MPG.
 
Demonracer said:
Instead of dealing with 30 to 50 year old parts, get an aluminum intake and a new Edelbrock 635 CFM carburetor. I 99% positive you will NOT see any decrease in fuel economy, I'll bet that it may get even better MPG.
Click to expand...

What would that do for me under 2500 rpm?
 
It's a tried and true combination, I've run that set up on 273's, 318's and mild 340's. I almost 99.99% of the cases, the fuel economy was better than any 2 bbl on the market. You will see no difference at a cruising speed at 2500 and under. You will see more and better performance when you plant your foot in it.
 
I would ditch the BBD and put a 1406 Edelbrock 4 bbl on it. Good starts, good economy, secondaries if you want a little Umff... and they don't leak gas like the bbd.

20200612_104857.jpg


20230124_110028.jpg


Night and day difference on how much better it ran, and still got 20 mpg.

☆☆☆☆☆
 
Demonracer said:
It's a tried and true combination, I've run that set up on 273's, 318's and mild 340's. I almost 99.99% of the cases, the fuel economy was better than any 2 bbl on the market. You will see no difference at a cruising speed at 2500 and under. You will see more and better performance when you plant your foot in it.
Click to expand...

Looking at Edelbrock's website, I'm not able to locate a "635 cfm" carb. I see various carbs in the 600 to 650 CFM range, with prices that range from $400 to $500.

$450 (USD) is $600 (CAD) for me. I'll add $200 for a suitable intake manifold, gaskets, etc. With tax that would probably bring me to $900 (CAD) total.

Just pulling numbers out of the air, if I saw an increase from 15 MPG to 20 MPG with the new carb, and if I drove the car 2000 miles a year (which would be quite a change from driving it zero miles in the past 25 years), the payback would take 4.5 years.

Is a 33% improvement in MPG realistic? Is 2000 miles a year realistic? Obviously this is not my daily driver (I probably drive less than 5k miles a year as it is).

So no, I don't think that spending $500 to $1k on a carb/manifold like that is in the cards. Putting half to a quarter of that money towards electronic ignition is more likely.
 
I don't see 33 percent increase in economy with a square bore 4 barrel and an intake alone,, unless it's intake designed for a low end power and mileage like the Edelbrock Steetmaster318, , with a spread bore with small primaries, or a 400 CFM AFB would work well
JMO
I've collected parts to build a "gas mileage 273 when gas gets crazy $$, this intake and card will top the engine

16960833241118245963705228178212.jpg


16960833443974210202776252000714.jpg


16960875585185226119785150080049.jpg
 
It sounds like the Monaco isn’t and won’t be a daily driver. If that’s the case, you shouldn‘t be using fuel economy payback as the justification for the replacement.

The payback for anything on a fair weather driver isn’t measured in $ savings but such things as enjoyment, pride and accomplishment.

Its reasonable to think the insurance cost you pay for it annually is pretty steep relative to the miles you drive it each year?
 
The car is not currently insured, and all the time it's beein in storage it hasn't been insured. Right now I have it at home, I drove it maybe 2 or 3 miles from where it's stored to home without insurance to work on it a little, I intend to drive it back to storage again the same way. Last year I did put insurance on it to drive, absolute bare minimum insurance, just what is legally required, no collision, just to drive it all of 10 or 15 miles total. Insurance companies here in Ontario don't offer plans for minimally-driven pleasure cars (other than Hagerty). My insurance cost (for the year) was roughly $600. But since I only had it insured for about a month, I only ended up paying $100. $100 for 15 miles of driving. Now maybe you see why I think insurance is a crock.

I was on Haggerty's website last year, I put in the details of the car, valued it at $5k, selected the lowest cost options, I think it came to $250 for a year, they don't seem to offer coverage for part of the year (like say May to October). I did that for curiosity, I didn't take them up on it. I have front suspension work to do, I recently bought a front stub frame in excellent shape that came from southern US that I may put on the car next year, so taking out insurance on it for driving in the forseeable future is not in the cards, but when it is I will look at Haggerty again.

Earlier this year I tried to insure a 2001 Chrysler 300m with them, filled out everything online, send photo's, driver's licenses, etc, and in the end they declined even through their website gave me a quote and everything. Of course I wasn't valuing the 300m at $20k, maybe that's the problem.

Regarding the carb, I was just wondering what my options were for aftermarket "ebay" carbs in the $100 range that would be bolt-on that would be superior to the "old-style" BBD, and specifically the "new style" BBD with lots of ports (and looks like built-in throttle return spring). I haven't heard a lot here so far about comparing the two, and by the sounds of it I don't think I'm going to.
 
Geez guys! After this thing set around for 2+ decades it might need a carb overhaul. Get a good kit and do that first before diving in with a intake and different carb.
 
toolmanmike said:
Geez guys! After this thing set around for 2+ decades it might need a carb overhaul. Get a good kit and do that first before diving in with a intake and different carb.
Click to expand...
For real, the BBD is a fine carburetor and it sounds like this one has low miles on it. Just a quality rebuild kit would do wonders for drivability I’m sure.
 
67CBodyGuy said:
The 318 (on my '67 Monaco) might be in need of a better carb, the only one I've ever known is the Carter BBD. I see them for sale on ebay for relatively cheap, about a hundred bucks, they look nice and new.

So here's my questions. I see lots of Carter BBD's for sale but basically they boil down to 2 carbs. One type is exactly what I have, only one or twp ports, the accelerator pump linkage is visable. The other type has a raised box around the accelerator pump so you really can't see it, and a LOT of ports that I'd have to plug. I'm assuming the carb with a lot of ports is a more recent design? Does it perform better? (Performance, as in getting the air/fuel mixture right, especially when idling, MPG, etc).

My other question, should I ditch the BBD and look at something else? That is still 2 barrel. Something that might give better idle, and the best city/highway MPG possible? If there's nothing that stands out here, then I'm back to question 1 above.

Thanks for any input.
Click to expand...
Jet up! Or grab a cutting torch tip cleaner and start honing out passages. I knew 1 guy took a BBD and took a torch tip cleaner to it and gave the carb back to the guy he worked it over for. He was clocked at 135mph. Supposedly. Never seen it, so I cannot testify to it.
 
1967 intake manifold undivided single plane. couple years later single plane divided. Later dual plane divided and stayed that way. Dual plane best for lower rpm, my guess. which do you have
 
I wrote down some numbers and made some measurements of jets and rods from my BBD and I have a couple extra old BBD and one or two BBS. See if I can find those numbers.

I see the term "solid fuel" mentioned on the web and in that Carter thread. What does that refer to?
 
Bugman said:
1967 intake manifold undivided single plane. couple years later single plane divided. Later dual plane divided and stayed that way. Dual plane best for lower rpm, my guess. which do you have
Click to expand...

Intake is 2468960 which seems to be 1967-69 (so it's the first casting made for the LA 318?)

Heads are 4027593 (1977-84) I think they have small air holes under each exhaust port that are covered by my exhaust manifolds (3830684).
 
There's an Amazon vender that is selling a couple different carbs branded as "Dromedary". The two carbs (about $140 CAD each) are:

Dromedary Carburetor Carb For Dodge Chrysler 318 Engine Carter BBD Lowtop 2 Barrel V8 5.2L MB-172-HCY

and

Dromedary Carburetor Carb 2100 Fits For Ford 289 302 351 Cu Jeep 360 Engine 2-Barrel A800

They're both 2-barrel, the 2100 model says will fit 1964~1978 Jeep Wagoneer Engine 360 Cu and a bunch of Ford but the hole spacing looks too wide for my intake.

What I don't get is that the first carb is listed for both 318 and the slant-6 so how can it be jetted correctly for both?

The BBD currently on the car has 1902 on the airhorn casting and 1933 on the body.
 
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