340 heads for a 318
#323451
05/20/09 10:33 AM
05/20/09 10:33 AM
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Joined: Apr 2009
Posts: 79
montreal, quebec, canada
jimmy71demon
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Joined: Apr 2009
Posts: 79
montreal, quebec, canada
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i have found a 340 complete engine that i think im gonna buy for my stroker project. now i only want the block right, but the guy wants to sell it complete. my buddy has got a dart sport with a 318 in it and its all apart too. what we want to know is: what (if anything) has to be done to either the 318 or the heads off the 340 to make them work together, and what the gain would be. also could he take the bottom end out and get his cylinders bored and turn his 318 into a 340? or is there clearance issuesin the bottom? thanks for the help guys jimmy 
Im goin fast Mom!
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Re: 340 heads for a 318
[Re: jimmy71demon]
#323452
05/20/09 10:45 AM
05/20/09 10:45 AM
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Joined: Apr 2007
Posts: 2,826
NY usa
540challenger
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master
Joined: Apr 2007
Posts: 2,826
NY usa
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Quote:
i have found a 340 complete engine that i think im gonna buy for my stroker project. now i only want the block right, but the guy wants to sell it complete. my buddy has got a dart sport with a 318 in it and its all apart too. what we want to know is: what (if anything) has to be done to either the 318 or the heads off the 340 to make them work together, and what the gain would be.
also could he take the bottom end out and get his cylinders bored and turn his 318 into a 340? or is there clearance issuesin the bottom?
thanks for the help guys
jimmy
The 340 heads will bolt right onto the 318 block no problem but you will want to you either a 340/360 intake as the port sizes are different.
You can use both the rods and the crank from the 340. There is a good chance the 340 will have a steel crank in it.
If it is a cast crank i would just use the 318 one.
The rods might work depending on the piston's you use 340's use a floating pin"not a pressed fit like the most 318"
Also depending on the year of the 318 the rods might not be any strouger.
The pistons are useless the 340 bore is 4.04 and the 318 is 3.91 standard.
Get a piston that will up the compression of the 318 from stock the 340 heads have a larger chamber
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Re: 340 heads for a 318
[Re: jimmy71demon]
#323455
05/20/09 12:21 PM
05/20/09 12:21 PM
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Joined: Apr 2007
Posts: 2,826
NY usa
540challenger
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master
Joined: Apr 2007
Posts: 2,826
NY usa
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Quote:
Quote:
Quote:
i have found a 340 complete engine that i think im gonna buy for my stroker project. now i only want the block right, but the guy wants to sell it complete. my buddy has got a dart sport with a 318 in it and its all apart too. what we want to know is: what (if anything) has to be done to either the 318 or the heads off the 340 to make them work together, and what the gain would be.
also could he take the bottom end out and get his cylinders bored and turn his 318 into a 340? or is there clearance issuesin the bottom?
thanks for the help guys
jimmy
The 340 heads will bolt right onto the 318 block no problem but you will want to you either a 340/360 intake as the port sizes are different.
You can use both the rods and the crank from the 340. There is a good chance the 340 will have a steel crank in it.
If it is a cast crank i would just use the 318 one.
The rods might work depending on the piston's you use 340's use a floating pin"not a pressed fit like the most 318"
Also depending on the year of the 318 the rods might not be any strouger.
The pistons are useless the 340 bore is 4.04 and the 318 is 3.91 standard.
Get a piston that will up the compression of the 318 from stock the 340 heads have a larger chamber
could he use 318 pistons on the end of the 340 rods? or would he have to oversize his block? if he oversizes to 4.040 then he would pretty much be running a 340 made from a 318 block right?
Depending on which pistons hey may be able to use it on the rods if you get aftermarket floating piston then yes.
however like i said the later 318 piston are just as strong as the 340 rods.
Also to overbore a 318 to 340 size must likely won't happen there won't be any meat left in the cylinders.
Have the 318 block taken to the machine shop have them clean it up and only bore it to clean up the cylinder no more.
You can get the 318 block sonic check to see if it can take the 340 bore but is a long shot imo
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Re: 340 heads for a 318
[Re: jimmy71demon]
#323457
05/20/09 03:20 PM
05/20/09 03:20 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
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Grand Haven, MI
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more or less....
BUT
the 340/360 have the ears for the drivers side motormounts closer together than the 273/318 (don't ask me why)
the 360 has larger main bearings, but a smaller rear main cap oil pan seal face (the cutout in the rear of a 360 oil pan is smaller than a 273/318/340)
they used unique internal sand cores when casting so they all have similar wall thickness. a 318 block will have similar cyl wall thickness as a 273, 360, or 340, so you can't just go and bore .130" over (to stock 340 bore size) unless you want to hit water, or have your cyl walls thinner than the sheetmetal on your fender.
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Re: 340 heads for a 318
[Re: patrick]
#323458
05/20/09 03:45 PM
05/20/09 03:45 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
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Az
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All good info here. The only thing I would suggest is that he buy pistons for the 318 to get the compression where it should be rather than cut the heads. By the time you cut the heads and manifold you have half the price of a set of pistons and you just narrowed down the use of the heads and manifold for any other applications later down the road.
Fastest 300
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Re: 340 heads for a 318
[Re: patrick]
#323459
05/20/09 03:49 PM
05/20/09 03:49 PM
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Anonymous
Unregistered
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Anonymous
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Quote:
the cutout in the rear of a 360 oil pan is smaller than a 273/318/340)
Are you sure that's not the other way around? (When I pulled the 360 out of the FJ40 and installed the 340, the only rear sump pan I had was for the 360. I cut matching sections out of the two pans and re-welded them.)
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Re: 340 heads for a 318
#323460
05/20/09 03:52 PM
05/20/09 03:52 PM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
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las vegas
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the 318/340 LA pan has the same size opening on the front and rear...
the 360 LA pan has a smaller rear seal size then the front...the front is the same as the 340.
the MAGNUM engines...318/360 use the same pan aka LA 360 pan seal size...
there is spacer that can be used on the 340 pan to fit the 360 block.
Tony
70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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Re: 340 heads for a 318
[Re: 70AARcuda]
#323461
05/20/09 04:14 PM
05/20/09 04:14 PM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Upper Midwest
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Quote:
Are you sure that's not the other way around?
Yes he is corect in that they are different and that the 360 is much smaller.
The rear pan seal on a 360 fits up into a groove in the rear main cap where on a 273/318/340 the rear pan rail seal fits on the pan rail itself and is the same front and rear.
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