318 to 340 swap questions

[907mopar]

So I️ found a running 340 that was in a truck for 1500 dollars. What am I️ going to need to do the swap besides passenger car oil pan?

 

[Adam]

Driver's side motor mount bracket might be different

 

[moparleo]

Every thing else will bolt right up. Did you get the trans as well? The Torque-flite for the 340 is the more heavy duty 727 as opposed to the light duty 904 used on the 318, some 360 . If you get the trans you will need to get your driveshaft modified to fit. Simple. Oh if your 318 was a 2 BBL the kick down linkage is different as well.

 

[907mopar]

No transmission just the motor. The car is already 4 barrel, so will kick down linkage be the same? Sticking with the 904 trans for now so motor mount on the drivers side is it then?

Also is 1500 a good price for that motor? It is a ‘69 and it’s on a run stand so I can check compression oil pressure.

 

[aussiemark]

If the block is close to standard bore and the crank hasn't been ground that is a good price but if the block is .060" over and the crank has been ground it is an average deal. You will need the good exhaust manifolds or headers the 318 exhaust manifolds have smaller ports and will choke it.

 

[DJ1967Dart]

Strange that it was in a truck. As far as I know the 340 was only sold in a performance vehicle, dart, duster, challenger, Cuda, roadrunner etc. Did you validate the engine is a 340 by the numbers on the side of the block? Not doubting its legit but a buddy of mine purchased a 318 Thinking it was a 340.

 

[907mopar]

Ya I also thought it was weird that he said it was out of a truck. I went ahead and passed on it anyhow. I think just don’t know how far I should go with this 318. It’s the original motor with 67,000 on it. I just keep seeing stuff I don’t like the further I dig into it. Ill try to upload a pic of the cam and you guys tell me what you think. It looks like it might start flaking??? The lines aren’t worn hardly at all though.

 

[907mopar]

Also I found these two chunks of metal when I pulled the intake manifold???

 

[moparleo]

If it is as dry as it looks, you have a major problem with the oiling system. I would pull the pan and do a proper lower end inspection. Oil pickup tube, screen, pump, bearings, etc... What does it look like under the valve covers ? 67,000 is not a lot of miles. It just depends on the maintenance done during those miles.

 

[907mopar]

As far as maintenance oil changes every spring for the last 10 years is all that’s ever been done. It we’ve only put 7,000 miles on it in that time. It sits a ton. It runs good and doesn’t burn oil or smoke. No blow by at all. But there is lots of sludge as you can see.

 

[moparleo]

Remove the distributor(mark location first @ tdc. Remove cam gear from bottom of distributor drive and then with a powerful drill motor get the proper allen head drive and run the pump for a few minutes. This will show you how much oil is actually getting up top and thru the motor. If it does not have very good flow the next step would be to get a can of engine flush ( or Kerosene and after draining the oil pour it in the lifter valley and run the drill again. This works much better when the engine is warm but you already removed the intake so just run the drill for several minutes or until it gets to hot and you need to let it cool down. But really, it is time ,especially with chunks of metal, to either rebuild. If you want the original block to the car, and go with a set of EQ heads or a complete long block. Ditch the flex fan as they are inefficient and prone to having blades come off with age. Lost a new radiator and hoses when one that looked real good lost a blade on the freeway on ramp while accelerating.

 

[aussiemark]

It would be good if we could figure out exactly what these bits of metal are off. They look like hollow dowels that have been squashed or maybe pieces of valve spring inner damper.

 

[Eric Griffith]

Every thing else will bolt right up. Did you get the trans as well? The Torque-flite for the 340 is the more heavy duty 727 as opposed to the light duty 904 used on the 318, some 360 . If you get the trans you will need to get your driveshaft modified to fit. Simple. Oh if your 318 was a 2 BBL the kick down linkage is different as well.

I got lucky when I changed out my engine and trans.
I had a donor car,that was a BB with a 727,and an 8 3/4 diff.
That driveshaft was perfect for my SB 727 Trans and diff combo.
I bought the Trans rebuilt for a 340 from a friend for $300 bucks.
Probably has less than 500 miles on it.
I let it sit too long once before (Kinda like now) and I had to pull the tail shaft housing off, so I could clean the Governor.
It had not been shifting correctly till I did that.
I am now putting shaved 360 heads on my 318,with thin gaskets,a 69 340 intake,and HIPO exhaust.
I'll need carb bracket linkage,kick down linkage,and modify the shift linkage for the Column shifter to clear the exhaust.

 

[mrjlr]

I'd stroke the 318 to 390. ....I will be doing this to mine hopefully this Spring.

Jeff

 

[Coupe]

I hotrodded the 318 in my car years ago using guidelines from an old HotRod magizne. You may find the article interesting to read even if you don't follow their suggestions. I have PDF's of the article if you would like for me to send them to you. Too much to copy and post here.

 

[Cudafor36]

I would not recommend the 904 tranny. Your 340 even a tired one will eat it up. Go with the 727 and you'll never have an issue. My 727 has taken a beating from my weekend get aways for the last 15yrs. Other than a front seal leaking it has been a tank.

 

[mrjlr]

I would not recommend the 904 tranny. Your 340 even a tired one will eat it up. Go with the 727 and you'll never have an issue. My 727 has taken a beating from my weekend get aways for the last 15yrs. Other than a front seal leaking it has been a tank.

Although i love my 727, a 904 is a very strong transmission and can handle a stock 340 just fine. And they can be built as strong as you want.

Jeff

 

[Cudafor36]

Good point on the build of a 904 but I've blown one when I was 17. Never do that again. The 727 is like a Sherman tank, even when your at 55mph and your girlfriend knocks the shifter into reverse. A scary bunny hop but no belt damage.

 

[Cudafor36]

So my comment on the metal fragments you found in the motor. See if it's a cast material by trying to break a peice in half and looking at the metal appearance. If cast it will look porous and could lead you to the root area it came from. If it bends and breaks it could be more ductile and not from a concerning motor component but rather a stamped plug or something else.

 

[907mopar]

Ok guys thanks for all the input. I waited too long to pull the trigger on the 340.

I pulled the 318 and found out that the pieces of metal where valve spring keepers and that the plastic cam timing gear was cracked and had a bunch of missing teeth. They were all Over the bottom of the pan and in the oil pickup screen.