340 Build. What's left?

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BlueDream

BlueDream

Aspiring Mopar enthusiast
Joined
Jan 22, 2014
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Location
Fayetteville, Arkansas
In about two weeks it'll be time for spring break which means I'll have some time off of school. While most students will be out partying and having fun, I'll be in the shop hard at work building the new engine for my Dart. I hope to have it done in about four days. Pull the 318 out on Friday, build the 340 over the weekend, then install it in the Dart on Monday.

I will have a complete carb to pan 318 to use as a parts engine too but I have a few questions. The 318 is from 1968 and the 340 is from late '72. What WON'T swap over from the 'teen to the 340? I know most differences but I feel like I'm forgetting something. I have the 340 cast crank balancer and the timing cover with the marks on the drivers side. My 340 is externally balanced so I bought a counterweighted billet flywheel and had the rotating assembly balanced. I also know that sometime in 1970(ish) the crank pulleys changed. Is there any way I could use the earlier 318 pulley on the later 340? I've also got Schumacher motor mounts in the car now and I'm going to shim the drivers side mount to fit the 340.

I THINK that I am about ready to get this bad boy built and installed. This is my first time completely rebuilding an engine from the ground up and I want to make sure it all goes smoothly and that I don't run into problems that would bring the build to a halt. Since I have already done the slant six to V8 swap I shouldn't have many problems actually installing the 340. Building it is going to be the challenging part. The 318 has less than 2,000 miles on a re-ring so the oil pump, water pump, timing chain, fuel pump, and any other parts I replaced are almost brand new and will go on the 340 along with any components that will swap over such as the Performer carb & intake. Heres what I have for the 340 so far:

Machined '72 340 Block
Rebuilt cylinder heads-
Main caps and bolts
Shot peened crank- turned & polished
Oil pan
timing cover- timing marks on driver side
Windage tray
Resized rods with ARP bolts
+.040 Pistons
340 Balancer
Billet Flywheel
COMP Cam & lifter kit
Fel-Pro Engine Gasket set
Fel-Pro Header gaskets
Fel-Pro Collector gaskets
Oil pump priming shaft
Lucas break in oil- SAE30 6 quarts
Royal Purple HPS- 10W30 6 quarts
Transmission tailshaft plug
Mopar HEMI Orange engine enamel paint x2
Moly Rings
Clevite Bearings- Rod & Mains. Cam bearings already installed.
Intermediate shaft bushing
Wix Oil filter x2
COMP Cam assembly lube- 8oz
ARP rod bolt lube
Engine stand
Fuzzy dice

Thats what I got in addition to my running '68 318 that's in the car now. I want to make sure I'm prepared for this. I'm going to basically be living in the shop working on it until it's done.. I'd really like to get it driving before spring break is over. Nothing would make me happier than to cruise to class on the first day back in my 340 Dart!

Do ya'll see anything that I either don't have or can't take from the 318? I'm all ears.
Any advise, tips, tricks, or general knowledge I can get would be much appreciated.

Thanks FABO!

Grant
 
I also know that sometime in 1970(ish) the crank pulleys changed. Is there any way I could use the earlier 318 pulley on the later 340?

Yes. One bolt hole will be slightly offset, file the hole to match the 340 balancer. Use timing cover, pulleys, water pump etc from the 318.
-Install the intermediate bushing and ream it if necessary before assembling the engine.
-Make sure all oil galley plugs are installed. Check this yourself before assembly starts.
-Check the cam bearings and make sure the oil holes line up that feed the cylinder heads.
I always use crane cams lube for break in lube on the lobes and lifter bottoms. It's a thick film that does not drip off like the stuff Comp Cams sells. summit sells the crane lube. http://www.summitracing.com/parts/crn-99002-1

Take your time and be methodical. Good luck.
 
I checked the block and the oil galley plugs are new from what I can tell. There were a couple that I couldn't see because of the way I've got the block sitting but I'll be sure to double check them all when I get it on a stand in the shop and out of my bedroom lol

Cam bearing oil holes are all lined up as well and I went ahead and ordered some of that Crane lube that you had a link to. I don't want to take any chances with damaging the cam or lifters. If it wipes a lobe and sends a bunch of metal through the engine, that would be a major setback.
 
In 1970 the water pump outlet to the radiator changed from the drivers side to passenger side. You will need a new water pump and/or radiator. Your 318 radiator won't be enough to cool the 340.
 
SoulSurvivor said:
In 1970 the water pump outlet to the radiator changed from the drivers side to passenger side. You will need a new water pump and/or radiator. Your 318 radiator won't be enough to cool the 340.
Click to expand...

And if you switch your water pump from one side to the other you wont be able to see your timing mark, unless you change your timing cover and your harmonic balancer.
 
trapster said:
And if you switch your water pump from one side to the other you wont be able to see your timing mark, unless you change your timing cover and your harmonic balancer.
Click to expand...

Very true. Forgot to throw that in there. With that being said I would buy an aftermarket Champion 4 core radiator for a '70 on up Duster. They are real easy to install and adjusting the fit is easy as well.
 
I've got an aluminum radiator with an electric fan and it does a great job of cooling the 318 so I don't think I'll have a problem cooling the 340. Dumping cash into a new water pump and radiator is NOT an option at the moment. I've got two timing covers though so I've got two options. Either run the timing cover where the marks line up with the balancer, or run the other one and mark the balancer to line up with the marks on the passenger side. Since I've had the rotating assembly balanced I'd rather not file into the balancer and I don't think painting a line on it would be enough, or would it? How hard would it be to see the timing mark with the water pump on the same side? Impossible or just inconvenient?
 
I was hoping to just run the 318 balancer, timing cover, and water pump but then as I read up more on 340's I found out mine was externally balanced so I threw that idea out the window. It would've made things a lot easier that way.
 
Not sure of this but wouldn't it be easier to just get a 72 radiator and then keep all of the 340 1972 parts ?
 
I don't have a 318 radiator though. I already have an aluminum radiator and don't see at I would need to buy another of what I already have is more than sufficient? Didn't 318 and 340 cars often use the same radiator straight from the factory?
 
My car isn't a factory V8 car and I didn't have a V8 radiator to use when I did the swap so that's why I just went with an aftermarket aluminum one. It's kept my 318 cool on 100°+ days in the summer and I have the electric fan on a toggle switch since the temperature activated one I had really sucked. I haven't had a problem with keeping it cool. The eBay radiator is basically what I've already got in the car and I find it hard to justify spending almost $200 on something that's pretty much what I already have...
 
Try to get your hands on a set of adjustable rocker from a 273. Also do you have a set of 340/360 exhaust manifolds (or headers) for it? Those 318 manifolds kind of choke the flow of the 340. What dizzy are you using and have you thought of the electronic upgrade for a better/more reliable setup?
 
I probably should have given more info on the car. It's a '73 Dart Sport that left the factory with a 225, A-230 trans, and an 8 1/4 rear end. I changed the engine to a '68 318 from a Fury III and retained the A-230 and 8 1/4. Its got Hooker Competition headers, 3" exhaust with an H pipe and flowmaster 40's dumped before the axle, it's got electric cutouts too. 3.21 open diff soon to be a 3.55 sure grip. Might swap the 3 speed for a 4 speed but I'm undecided as I like my 3 speed and it's fun with the pistol grip. I basically want to just drop in a 340 long block in place of the 318 long block and keep everything else the same
 
1970Duster said:
Try to get your hands on a set of adjustable rocker from a 273. Also do you have a set of 340/360 exhaust manifolds (or headers) for it? Those 318 manifolds kind of choke the flow of the 340. What dizzy are you using and have you thought of the electronic upgrade for a better/more reliable setup?
Click to expand...

273 rockers are definitely on the list but I have normal rockers for now. Dizzy is stock replacement '68 with points but the car came with electronic ignition so it should be pretty easy to swap back. I got the distributor with the engine so that's why I used it. I just haven't decided on a replacement for it yet. MSD is pricey and Id want the E-Curve since i could just dial in what I want it to do and it doesn't require an external box. HEI is cheaper but I've heard good things about it, and then Mopar is good but more expensive than the HEI. I've put some thought into it but haven't decided which route to take yet. Probably not MSD since my car will be 99% street and 1% strip. The whole exhaust should be fine for this 340. It was a bit overkill for the 318. After the 340 goes in Im going to start saving for upgrades. Holley 750 double pumper, air gap intake, rear end rebuild, transmission rebuild, completely new ignition setup.
 
Here's a pic of the car when I backed it out of the shop after breaking in the 318.
 

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BlueDream said:
I've got an aluminum radiator with an electric fan and it does a great job of cooling the 318 so I don't think I'll have a problem cooling the 340. Dumping cash into a new water pump and radiator is NOT an option at the moment. I've got two timing covers though so I've got two options. Either run the timing cover where the marks line up with the balancer, or run the other one and mark the balancer to line up with the marks on the passenger side. Since I've had the rotating assembly balanced I'd rather not file into the balancer and I don't think painting a line on it would be enough, or would it? How hard would it be to see the timing mark with the water pump on the same side? Impossible or just inconvenient?
Click to expand...
Just an inconvenience. Getting a timing light on it will be a balancing act. No long hair. Watch timing light cables and your elbows. I've done it. But my harmonic balancer has hash marks on both sides of the TDC marking. It was $$$ well spent.
No. The /6 or 318 radiator was not the same one as the 340. And neither were the water pumps. Those engines weren't designed to rev to 6000rpm. But as long as your water pump outlet and bottom of the radiator line up then you are home free. As long as they hold up to a stock 340.
 
BlueDream said:
273 rockers are definitely on the list but I have normal rockers for now. Dizzy is stock replacement '68 with points but the car came with electronic ignition so it should be pretty easy to swap back. I got the distributor with the engine so that's why I used it. I just haven't decided on a replacement for it yet. MSD is pricey and Id want the E-Curve since i could just dial in what I want it to do and it doesn't require an external box. HEI is cheaper but I've heard good things about it, and then Mopar is good but more expensive than the HEI. I've put some thought into it but haven't decided which route to take yet. Probably not MSD since my car will be 99% street and 1% strip. The whole exhaust should be fine for this 340. It was a bit overkill for the 318. After the 340 goes in Im going to start saving for upgrades. Holley 750 double pumper, air gap intake, rear end rebuild, transmission rebuild, completely new ignition setup.
Click to expand...

That msd ecurve dizzy is a damn good unit (I have one for my 340)! Even if it's just a street car, you'll still benefit from it. I see you have 8.25 rear (which I'm also assuming you have front disc brakes) go to the junkyard and grab the rear disc setup off a 96ish Jeep grand Cherokee for a cheap easy bolt on rear disc setup. Yea I know it doesn't have anything do with the 340 per se but all the power in the world doesn't mean anything if you can't stop. Just good for thought.
 
1970Duster said:
That msd ecurve dizzy is a damn good unit (I have one for my 340)! Even if it's just a street car, you'll still benefit from it. I see you have 8.25 rear (which I'm also assuming you have front disc brakes) go to the junkyard and grab the rear disc setup off a 96ish Jeep grand Cherokee for a cheap easy bolt on rear disc setup. Yea I know it doesn't have anything do with the 340 per se but all the power in the world doesn't mean anything if you can't stop. Just good for thought.
Click to expand...

Yes I have front disc brakes. I've called some places around here about getting the rear brakes from a Jeep and they want to sell me the whole thing. No way no how am I going to buy a whole rear end just for one part. I'll keep calling around and I'll probably find a place that will sell parts instead of the whole rear. I plan to do rear disc brakes when I have the rear end out for a rebuild that way I can just get it all done at once. So is the E-Curve worth the price over everything else? I love the simplicity and functionality of it. And the built in rev limiter will be a nice thing to have too. I've been trying to get a 340 in this car for years but it never seems to work out due to lack of money or outrageous prices, or sometimes both. It feels good to be this close even if it won't really reach its full potential right away. Like the rest of the car, I'll get it done one upgrade at a time. It just better be faster than my 318 lol
 
^^^I think the msd ecurve is worth it! I know autoxcuda has one and maybe 72bluNblu(?) has one as well.
 
1970Duster said:
^^^I think the msd ecurve is worth it! I know autoxcuda has one and maybe 72bluNblu(?) has one as well.
Click to expand...

I'll try to get one this summer then. After ignition I'll get 273 rocker arms and do the recommended mods to them. I think it'll be money well spent!
 
So is there anything else I need or should I be all set to assemble this engine? If I need to order anything else, now is the time.
 
Looks like you need a Hood,
but seriously I have never been a fan of Felpro head gaskets, especially if you are running any kind of compression.
 
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