Got Shell 93 Octane and now barely idles 1973 Dart 340

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You probably need to know about any possible change in crank balance, and whether the new engine comes with it's own damper and balance factor for your TC.

After that, you are gonna need three things;
1) New tires
2) a buddy to share the excitement with, and
3) some clean underwear, cuz; Your new engine is a 360, and not just any 360, but an M-R-L 360
 
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TRWRacing said:
Is there anything that I need to be concerned with swapping the 340 for the 360 that will not be compatible?
Click to expand...

Make sure you find out if the correct flexplate/TC combo, and the correct crank damper, comes with the new 360, or get the right 360 parts. 360's are known as 'external balanced' (which is actually 'partially externally balanced' to be correct). This means the damper on the front end, and the flexplate and/or torque converter on the back end, are intentionally imbalanced to aid in the overall engine balance. You can't use 340 parts because:
1. The 72 and earlier 340's have no imbalanced external parts.
2. The 73 340's do have imbalanced external parts, but they are a different level of imbalance vs 360's. So if you have an imbalanced 340 torque converter, that imbalance is not right for the 360.

For the 360 front end of the engine, it has to have a 360 crank damper. On the 360 back end, it can either have a neutrally balanced flexplate + an imbalanced torque converter, OR an imbalanced flexpate + neutrally balanced torque converter. The B&M 10236 is an example of an imbalanced 360 flexplate for the 727 trans.

I hope that all makes sense....
 
That is good new to hear that I made a good decision. I put at deposit down and spoke with Mike about my current 1973 340 with a 727 transmission. He did say it comes with the 360 damper and flexplate. I need to give him a call to confirm the electric choke on the carb and will confirm that I need the 360 to be balance correctly to match the transmission. I did not know for sure what the current year engine/trans is in the car, just what I was told at the sale.

So if it comes with the 360 LA damper and flexplate, then do I still need something for my 727 torque converter? Sorry, I am relearning the Mopar specifics from my high school years (mid 1980s).
 
Good deal on the 360 damper. And no problemo... we all started in this world knowing exactly zero!

Find out if:
1. The flexplate being provided is balanced and is to be used with a 360 TC, in that case, you need to get a imbalanced TC for a 360.
or
2. The flexplate being provided is imbalanced and intended to be used with a neutral balanced TC, in which case you get a neutral balanced TC or knock the weight off of your 340 TC.

You do know that the MRL 360 Classic Cruiser is going to totally spoil you right? Just PM ME when you are ready to dump the 340....I could use another one LOL
 
nm9stheham said:
Good deal on the 360 damper. And no problemo... we all started in this world knowing exactly zero!

Find out if:
1. The flexplate being provided is balanced and is to be used with a 360 TC, in that case, you need to get a imbalanced TC for a 360.
or
2. The flexplate being provided is imbalanced and intended to be used with a neutral balanced TC, in which case you get a neutral balanced TC or knock the weight off of your 340 TC.

You do know that the MRL 360 Classic Cruiser is going to totally spoil you right? Just PM ME when you are ready to dump the 340....I could use another one LOL
Click to expand...

Thank you nm9stheham and AJ/FormS! The Mopar expertise of you two is invaluable.

I have been given a lot grief from the wife over this and was told no surprises with making this 360 work. All on top of the additional stress regarding my Dad and helping my Mom through a difficult time.

It was hard father's day and even more when you can't enjoy your car.

I will find out about the flex plate tomorrow.

Thanks again for everyone's input.
Eric
 
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It will be
2. The flexplate being provided is imbalanced and intended to be used with a neutral balanced TC, in which case you get a neutral balanced TC or knock the weight off of your 340 TC.

I called this morning to confirm and added on Mopar Performance cast black valve covers, which go good with the paint which is B5 blue with a black duster 340 stripe and black interior.

Can't wait it's like waiting for Christmas.
Eric
 
If I change out the torque converter to a netural balanced one instead of knocking off the weight of the 340TC, which one do you recommend?
Also, I was having a front trans leak that would drip down to the edge of the bell housing. It is red trans fluid and the pan gasket and neutral safety switch and plug has already been replaced. What might be leaking? I liked to get that buttoned up as well.

Thanks!
Eric

22700_b78011feb3_low_res.jpg


22731_1b664c49c9_low_res.jpg
 
Torque converters seal or perhaps pump gasket.

I don't consider myself the best with torque converter selections, so I think you can get better advice that from me. Maybe post in the transmissions section, or see what MRL has to say. They know the torque curve of the engine and I bet would have a good idea. Make sure you tell everyone what the intended usage is.
 
That could be one or more of several things.
OOps nm9 beat me to it,
I will add that the tranny vent is in the bell too, so see if it is wet way up high on the passenger side. If the tranny fluid is too high or if it gets too hot, it will sometimes puke a little fluid out there. Then it may not leak again for weeks or months.
If the fluid is on the TC only then it is probably the pump seal.But it could also be a cracked TC-nose.
If the front gasket leaks(rare), it could be wet anywhere. Occasionally the little seals under the pump retaining bolts will leak.

Knocking the weights off is not a thing to be feared.But MRL is probably the go-to guy on this combo.
 
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More info and not what I was originally told. The piston rings should not fail in 18K miles.

Eric

I don't know why the 9 would be scratched out nor does it matter to me as odometer reading doesn't hold any credence 44 years after being mfg'

especially when the car is not original anymore

I bought the car in California in the early 90's from the original owner who had it for sale at the Pomona swap meet at the Los Angeles fairgrounds complex

The paint was wearing off from the california sun and wind , and the vinyl top was cracking but the car was virtually rust free except for the rhlower quarter behind the wheel opening

They hold a swap meet there every 6 weeks or so and there are a lot of cars there for sale

I used to travel there to buy cars because I was tired of the rusty midwestern cars even back into the 80's

I would buy them and have them shipped by transport back to st louis

The car did not have enough anti freeze in it when I had it and the block froze and broke during a cold winter

I was very upset about this , decided to get the car gone and I then sold it as is to Dennis Fehl as he used to own a grey 72 Dodge Demon

and this was close to that car in appearance and heavily optioned , and he restored it in the 90's and kept it till last year( 20+ years)

Dennis is a meticulous fellow, he was very fond of this car and after 20 + years , I purchased it back from him. He owns his own Muffler shop for the last 40 years working by himself without

employees ...he is the best exhaust guy in the area

He had a block found for the car, had the engine rebuilt around 1995 and drove the car off and on for 18000 miles not 3000 miles, as I called him today to verify these facts ....

He told me today that the car had 77XXX when he bought it with the bad motor and it had around 94000 when he sold it...but could not remember the exact miles when sold

as all 10 year old or older cars are sold miles exempt ...so it had 17000 miles approx on the rebuild

The miles on the odometer are what is considered to be on the body and chassis...not the mechanical

There is your explanation about the scratched 9 , no one here scratched it and no one here are concerned about the 9 being scratched as it is what it is ...scratched


regards
Mark H***
 
Still patiently waiting for new engine. Can't wait.

I did reach out to where I bought car from. They stated since it was bought 9 months regarding in it sat in the garage for 7 of those 9 months nor the 300 miles.

They wanted me to ship the car 320 miles to them for $600 round trip and they would fix the piston ring. I said unacceptable and wanted some from of money compensation.

Do you really think an engine with 40% leakage on 2 cylinders or more can be fixed with new piston rings? Sounded like a ploy for more money surprises.

Their mission statement states that they "examine every car extensively before we purchase so we can ween out the problem cars before they get to the customer." So much for that since it was the Service Mgr's personal car.

Lesson learned any time looking at a classi car, I will bring a compression tester and vacuum gauge.

New engine in my mind was the best choice.
 
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I think your choice was the best way to go, getting a 'brand' new engine from a highly trusted "local" engine builder might be costing you but it will be a "once and done" deal where once that fresh 360 is in there you will never have to worry about it again.

Another point, when I got my 360 balanced at the machine shop I gave them a weighted B&M flex plate I got with a bunch of other parts; I got a call one day saying the balance on the flex plate was way off and wouldn't work with my 360, and later the machinist told me he figured out it was a plate for a 1973 cast-crank 340. Apparently the 1973 340 are balanced differently than 360s, at least according to my experience?
 
MOPEkidD-3 said:
I think your choice was the best way to go, getting a 'brand' new engine from a highly trusted "local" engine builder might be costing you but it will be a "once and done" deal where once that fresh 360 is in there you will never have to worry about it again.

Another point, when I got my 360 balanced at the machine shop I gave them a weighted B&M flex plate I got with a bunch of other parts; I got a call one day saying the balance on the flex plate was way off and wouldn't work with my 360, and later the machinist told me he figured out it was a plate for a 1973 cast-crank 340. Apparently the 1973 340 are balanced differently than 360s, at least according to my experience?
Click to expand...

Totally agree on the new engine. The piston ring repair sounds shady and I am not shipping my car 300 miles away.

I was told that the 360 will with the flex plate to run a neutral balanced torque converter or knock the weight off my 340 TC - 727 trans.
 
@MRL Performance if you're around maybe you can shed some light? Basically what my machinist figured out was the amount of offset-balancing between the two engines is actually different (1973 340 vs. 360)...
 
Take the carb off and get a clean bowl and turn the carb upside down and shake it until it's emptied all the gas in the bowl,it'll come out thru the air horn.
You see water? If not it's not water and more than likely a vacuum leak. Always a possibility a small piece of grit made it to a idle passage.
Don't forget to remove the fuel filter and empty it into a bowl and look for water or trash.
 
My new 360 MRL engine is arriving today! A Big Thank You to Mike at MRLPerformance!!! He is a great guy to work with. New TurboAction 11" 2500 Stall TC is on the way as well. I am excited to get the installation process starter next week with my installer.

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