Hi,new member here. I have a 1970 dart swinger with 225 slant six,this is my first "newer" Mopar and first slant six.
The car currently has an aftermarket (I am assuming it's a stant) locking gas cap that doesn't fit snugly,it wobbles when you touch it. Would someone here be able to tell me the correct original Mopar part number for the genuine mopar locking gas cap?
Is there a difference between a 1970 "california" dart vs a dart sold outside ca? I ask because in attempting to find an answer to this question I read that 1971 california cars have some unusual filler neck and require a one year only cap. Don't know if it's true or not.
Thanks in advance

49-state/Canada '70 cars use a filler neck and cap compatible with the '67-'69 cars. California '70 cars and 50-state/Canada '71 cars use a filler neck and cap all their own. '72-'76 cars use yet another kind of filler neck and cap.

The '70 California + '71 parts are very difficult to get, and there is no factory part number for a locking cap for that application. The aftermarket companies (Stant, etc) might at one time have provided locking caps for that application, but finding one now will be a "go fish" operation.

Me, I would install a '72-'76 filler neck (preferably a '75-'76 item from a car with the unleaded fuel/catalyst package; those have a flapper and insert that prevents annoying splashback when filling.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks for the information. Boy! I have to love California and their ridiculous regulations.i had no idea that idiocy started that far back. Obviously this special neck wasn't such a great idea since only two years are saddled with it.

I honestly don't want to alter the car from stock,I personally like the old style open filler necks like the 50's and 60's cars have. It makes it so easy to fill them from a gas can if you run out of gas.
If anyone out here knows what stant part number fits it,or if a mopar cap was available I will keep watching ebay.
Is there any chance my car may have escaped having this dreaded California filler neck? What are the measurements for the 69 opening? The opening on my filler measures about an inch and a half.

I know I do! Just imagine how bad the smog would be today if California hadn't started passing laws to reduce vehicle emissions.

See HERE and skip to 45:30.

Yep,if they didn't design this filter neck we'd all be dead now. I guess if you're so concerned about the environment you wouldnt be driving an old car like this anyway,right? Better yet,don't drive a car at all,you can bike everywhere or maybe ride horses again. Lol!
Nobody's arguing that SOME of the regulations didnt help curb smog,I would assume most to understand what I meant. But we (state of california) go overboard with moronic opressive mandates and idiotic regulations. at one point they were talking about making it a ticket able offense if you were seen driving with under inflated tires because it wastes gas. We still have to smog 76 and later vehicles when there are practically none on them on the road as daily drivers. How about Ethanol in gas anyone? That was a bright idea.
Stupid things like this filter neck didn't make a difference anyway. They wouldn't have redesigned it after two years if it did.
Anyway There are enough other people driving new plasticars that the emissions from the few old cars out there DONT even matter at this point. And it seems to me anyone obsessing over smog wouldn't be driving something like this anyway

Anyway,if anyone knows what the correct cap is if appreciate it.

Yep. I have a friend born in 1948 that grew up in Glendale, CA. In the late 50's they had horrible smog. The finally banned burning garbage and then started in on vehicle emissions with PCV systems and other very basic controls/devices. LA being an overpopulated basin they had to take drastic action. Had the US auto manufacturers not be so penny wise and pound foolish we would have had EFI and good running engines in the late 1970s as the European cars did. As it was my parents bought a 1973 Civic new. Grandparents bought a 1974 Plymouth Scamp new. Guess which one started easily, ran well and consistently stayed out of the shop!?

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Joshua

Why are you hijacking this thread and turning it into a debate about Japanese cars vs american technology and smog devices? This is a site about old Chrysler products with slant six motors? I don't own any modern cars with smog crap on them and have never had my dart or other mopars in the shop. The few issues I have had (u-joints,fuel pump,etc) I have been able to repair cheaply on my own.
This swinger starts everytime all the time and unlike a fuel injected overcomplicated import,the pump can be easily replaced by removing two bolts,a line in and a line out. Fuel injected cars have an electric pump in the tank turning replacement into a drawn out ordeal.
You like modern cars? wonderful,I am happy for you. to each his own. But I didn't join this site to argue about smog devices or how inferior you feel our mopars are compared to import cars technology. They are what they are and these engines have a longnstanding reputation for relaibilty and longevity. I started a thread about a gas cap. Obviously you have nothing constructive to contribute to the topic at hand,right?

And again,I never said all smog laws are bad,or that something Shouldnt have been done to help clean up the air,but again,this site is about old mopars with slant six engines,why drive an old car if you are so worried about that to begin with?

I drive a 1951 car. Even though I live in a part of the world that has never had smog testing I am proud to say my car would likely pass a smog test for a 1991 car.

It would not get a 5 star crash test rating ....but it a much safer auto now than when it was built.

Driving an older auto does not mean you get a bye on caring about the world we live in.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Agreed. All my cars are well maintained and don't smoke or leak oil,etc. and I also agree there are new cars which probably pollute more and use more gas than your 51. I see modern cars on the road blowing oil out the tailpipe all the time and wonder how they get their tags.
Again though as far as our cars It's really a non issue since there are so few 50's,60's and 70's cars used as daily drivers anyway. And if they are well maintained they do run pretty clean.

These cars are what they are,they are products of their time. I'm not going to stay up nights worried about the fact my dart doesn't get the same mpg's as a prius.
What make and model is your 51?

Sorry, it was my post that went off topic. I apologize to the board members and the moderators.

Back to the topic,is there anyone here with a non California dart or a 69 dart that could measure their filler neck opening? I am curious what the size difference is between them. I measured the opening on my 70 and it is 1 1/2" not counting the notched cut out for the cap wings.

I am hoping somehow I may have the earlier style opening. I know someone with a mopar locking cap for the 69 style

Just to veer back off topic for just a second, I smog tested my slant even though it's technically exempt because I wanted to see just how bad the stuff coming out the pipe really was. Even without a catalytic converter, smog pump, EGR, or fuel injection it tested cleaner (overall) than my brother's Chevrolet half ton Silverado 5.7 with those items installed. Old cars don't necessarily have to be gross polluters if they're tuned up properly.

As for the locking gas cap, I wish you well in your quest. I haven't seen such a device offered for sale around here in quite a while for cars other than the plastic screw cap design modern cars have.

But here's an idea I read somewhere on the interwebs: a guy wanted to keep his Chevelle looking stock and having a stock gas filler neck, but didn't want his expensive racing gas stolen. So he welded a sink drain at the other end of the filler tube. Looked stock at the cap end, but a siphon hose wouldn't get very far. Just a thought.

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If it was easy, everybody would be doing it.

Hi Coconuteater,Thats good to know! it always burns me when people blindly give old cars a bad rap as "gross polluters". There really are wackos out there who would like all of these cars off the road.
I read something similar in an automotive magazine once,I think it was in Hot Rod where a 64 Mustang they tested came out as clean as a late 90's mustang. Someone also did one on YouTube with a 57 chevy and it would have passed emissions in necessary. As you pointed out,if you slant six was as clean as a car with all the modern smog devices it makes you wonder just how necessary all that stuff really is.

Thanks for the advice on the cap. I honestly had no idea when I bought the car that this was a special year for the filler neck. I had heard conflicting info on the subject,some saying that not all California 70's had the 71 style filler,that's why I joined this site. I figured there had to be someone here who dealt with this who would have an answer. If we lived in more trusting times it wouldn't be such an issued about having a locking cap,but gas theft went up with gas prices.

Back after Hurricane Katrina gas thefts were common around here because gas was $5 a gallon for a while. Locking gas caps weren't much deterrent because the thieves were just puncturing the bottom of the plastic tanks under the car and letting the gas drain into a pan. I hate gas thieves!

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If it was easy, everybody would be doing it.

Me too,the gas thieves hit the local uhaul out here a couple times and stole gas out of the trucks and moving vans when it went over $4.00. Now it's back down to $2.59 at the cheapest stations. I had no idea gas tanks were made of plastic nowadays. I guess it shouldn't surprise me since most of today's cars are largely plastic.