340 tune up

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Toddbluedorn

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Hey everybody, new member here and hopefully soon to be proud owner of a 71 Plymouth duster 340 assuming the engine is a bit tired and in need of a tune up I know I’ll have to do intake, carburetor, exhaust, oil change, coolant flush, maybe a new radiator spark plugs, ignition wires, distributor, you know all the stuff that takes a lot of wear and tear but I’m wondering if anyone could help me about replacing valve train components (lifters, springs, rockers, etc) for reference it has a torque flight it’s gonna be an A to B car but I want it to have a bit of Pep so with that being said what should I get to help bring an ol’ 340 back to life!
 
Welcome aboard!:canada: I just finished building installing my 340. Lots of fun with lots of help here!
Make sure to have good tools. Degree wheel, valve spring compressor (diy, cheap and easy). Harmonic puller, dial indicator.
Have fun!
 
Beware of New lifters as they are junk these days. Have your factory ones resurfaced if possible. Not much money to have done.
Welcome to the site and enjoy. Lots of helpful members here.
 
Run a compression test on the cylinders to see were your at. That will give you some insight on how far you have to go with it
 
Welcome and good luck. There is a ton of information on this sight to learn from
 
that ain't no tune up, that's a top end rebuild!

i'd run a compression test and a leak down to get a baseline and then do an overall assessment of what you've got going on before jumping in deep.
 
junkyardhero said:
that ain't no tune up, that's a top end rebuild!

i'd run a compression test and a leak down to get a baseline and then do an overall assessment of what you've got going on before jumping in deep.
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Yep. Do this and go from there.

My 66 barracuda still has the original radiator. A lot depends on how well it was maintained.

Welcome to FABO. Have fun with your car as you get into it.
 
Toddbluedorn said:
Hey everybody, new member here and hopefully soon to be proud owner of a 71 Plymouth duster 340 assuming the engine is a bit tired and in need of a tune up I know I’ll have to do intake, carburetor, exhaust, oil change, coolant flush, maybe a new radiator spark plugs, ignition wires, distributor, you know all the stuff that takes a lot of wear and tear but I’m wondering if anyone could help me about replacing valve train components (lifters, springs, rockers, etc) for reference it has a torque flight it’s gonna be an A to B car but I want it to have a bit of Pep so with that being said what should I get to help bring an ol’ 340 back to life!
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Lets see some pics of the Duster
 
340? no it cant be...( just kidding ) but 340 threads are somewhat rare... :thumbsup:

P.S. whatever ya do don't ask Uncle Tony about tuning anything... :poke: :lol:
 
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CFD244 said:
Welcome aboard......Slap a 360 in it :) :poke:
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Why go half measures? Hemi swap it. :lol::lol:

Actually, doing a basic tune-up and maybe a carb change/rebuild would be the first step. Then drive it a while and check compression and such. Don't forget to go through the braking system and check ball joints. If you got lucky, you have one of the high compression 71 motors, I think they dropped compression at the end of the model year. Anyway, you'll know where you stand for potential cam change, etc.
 
Toddbluedorn said:
Hey everybody, new member here and hopefully soon to be proud owner of a 71 Plymouth duster 340 assuming the engine is a bit tired and in need of a tune up I know I’ll have to do intake, carburetor, exhaust, oil change, coolant flush, maybe a new radiator spark plugs, ignition wires, distributor, you know all the stuff that takes a lot of wear and tear but I’m wondering if anyone could help me about replacing valve train components (lifters, springs, rockers, etc) for reference it has a torque flight it’s gonna be an A to B car but I want it to have a bit of Pep so with that being said what should I get to help bring an ol’ 340 back to life!
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Whoaaa, Nelly! Slow down a minute, pardner.
Some basics, first.
Is this a running, driving car, or a derelict you pulled out of a field somewhere?
If it's a runner, no need to dive that deep into the engine (at least not yet).
Start with an actual tune up- plugs, points/condensor, plug wires, cap and rotor, air filter, fuel filter, oil change and filter. Get good parts and not cheap dime-store stuff that cause as many issues as they solve.
Then get a good timing light and distributor wrench, and a tach/dwell meter; and start reading up on how to use them.
There is absolutely no reason to start diving into lifters, springs and rockers; much less intake and carb until you have actually established a need for them. 340s came with some of the best engineered parts ever available on a factory small block, and replacing major components willy-nilly will only lead to more issues and possibly a big step backward.
Don't worry about giving it "a bit of pep", once you've got it running well a 340 will have enough "pep" to scare you.
So, first things first- is this a runner or something that's been at the bottom of a creek for 20 years?
 
Toddbluedorn said:
Hey everybody, new member here and hopefully soon to be proud owner of a 71 Plymouth duster 340 assuming the engine is a bit tired and in need of a tune up I know I’ll have to do intake, carburetor, exhaust, oil change, coolant flush, maybe a new radiator spark plugs, ignition wires, distributor, you know all the stuff that takes a lot of wear and tear but I’m wondering if anyone could help me about replacing valve train components (lifters, springs, rockers, etc) for reference it has a torque flight it’s gonna be an A to B car but I want it to have a bit of Pep so with that being said what should I get to help bring an ol’ 340 back to life!
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Welcome to FABO!
Where in the Lone Star state are you?
 
Professor Fate said:
Whoaaa, Nelly! Slow down a minute, pardner.
Some basics, first.
Is this a running, driving car, or a derelict you pulled out of a field somewhere?
If it's a runner, no need to dive that deep into the engine (at least not yet).
Start with an actual tune up- plugs, points/condensor, plug wires, cap and rotor, air filter, fuel filter, oil change and filter. Get good parts and not cheap dime-store stuff that cause as many issues as they solve.
Then get a good timing light and distributor wrench, and a tach/dwell meter; and start reading up on how to use them.
There is absolutely no reason to start diving into lifters, springs and rockers; much less intake and carb until you have actually established a need for them. 340s came with some of the best engineered parts ever available on a factory small block, and replacing major components willy-nilly will only lead to more issues and possibly a big step backward.
Don't worry about giving it "a bit of pep", once you've got it running well a 340 will have enough "pep" to scare you.
So, first things first- is this a runner or something that's been at the bottom of a creek for 20 years?
Click to expand...

Have to agree with post #13. The 71 340 was probably the best small block package ever produced. Almost everything is heavy duty to last hundreds of thousands of miles. It had the best intake, Carb, heads, rockers, springs, double roller timing set. My 71 340 was still breaking into the 13's with 100,000 miles on it.
 
66fs said:
Have to agree with post #13. The 71 340 was probably the best small block package ever produced. Almost everything is heavy duty to last hundreds of thousands of miles. It had the best intake, Carb, heads, rockers, springs, double roller timing set. My 71 340 was still breaking into the 13's with 100,000 miles on it.
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I don't disagree with this statement at all, but sometimes things are not what they seem. The 71 340 that came in my car turned out to still be standard bore with the high compression pistons and 2.02 J-heads. BUT, it had a forged 318 crank in it.:wtf: I doubt it was properly balanced but it still ran pretty respectfully. That car had a lot wrong with it as I found out later, so I'm not surprised about the crank.
 
First download a factory service manual from Service Manuals – MyMopar

Do the basics, compression test, plugs, plug wires, timing, carb adjustment.

Transmission inspection / top off or fluid replacement.

Rear differential fluid check/drain and refill if necessary.

Inspect the brakes, shocks, suspension etc, get to know your car.

Take some photos, make notes etc.. document where you are starting from as well as the progress of your project.

I would definitely drive it for a few months to get to know what is or what is not working to your expectations before I tore into a major bunch of changes / modifications.

Make a list of the things you would like to update, replace or modify.

Lots and lots of great folks, vendors with plenty of and no shortage of smart asses too.

Welcome to the site.
 
gzig5 said:
I don't disagree with this statement at all, but sometimes things are not what they seem. The 71 340 that came in my car turned out to still be standard bore with the high compression pistons and 2.02 J-heads. BUT, it had a forged 318 crank in it.:wtf: I doubt it was properly balanced but it still ran pretty respectfully. That car had a lot wrong with it as I found out later, so I'm not surprised about the crank.
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Also, What does he really have and what has been done to it, considering it is now 54 years old...
 
68-71 long blocks (Sans 68 4 speed cam deal or TA block/heads) are essentially the same. Same cam, compression. The spinning parts aren't different.

915 vs X heads roughly same.

The 71 got a TQ carb/manifold. That was the difference. Also got the bad pass side exh manifold. Should have left the sweep manifold vs log style.


I would not be tearing into an engine without doing some test to see if it's a viable runner. I've started stuff in an hour that sat for 30 years. Check dipstick, radiator, socket on crank bolt to see if it turns over by hand, change oil/prime it, etc. Do the simple stuff before ripping it apart for no reason.
 
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