Just a FYI. 340 forged crank to the left 318 forged crank to the right. Same forging, completely different balance requirement. 340 has the drilled 1-2 /7-8 throw to allow for the heavier pistons in a 340.
70 318 with 340 internals/Cyl Head
- Thread starter mario03srt
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340sFastback
Well-Known Member
'72 and '73 340s had the smaller intake valve, the cast cranks, and lower compression by sinking the heavy pistons into the bore.
Some of the early 72s may have but the later ones were cast.
340sFastback
Well-Known Member
Yeah I have heard of early '72s having forged and sometime during production of '72s they switched to the cast cranks. Most likely Chrysler wanted to use what ever forged cranks were left over from '71 and then switch to cast.
This is exactly what happened, I have one and it was ground undersize .02 rods and mains from the factory and is stamped as such with factory markings.
Ironracer
Gearhead
It will not change the displacement, but will change airflow. That translates into horse power.
Wow. A lot of misinformation here. Car 318's had forged cranks in 1967 only. From 1968 up 273's and 318's had cast cranks. Not that it really matters since they are plenty strong. 340's had forged, shot peened cranks with drilled throws, see post#76, from 1968-1972 partial. 1972 partial and 1973 340's had cast cranks externally balanced. All 273's, 318's, and 1968-1972 partial 340's were internally balanced. All 273's and 340's had floating, brass bushed pin, rods. 318's had floating, light rods, and pressed pin, heavy rods. The heavy duty rod forgings could be found in 340's, 360's and later 318's and had the same forging # in the same time period.
As for the 318/340 internals, it makes little sense to discuss unless you know what internals we are talking about. What does it matter if the OP drives it and it performs to his satisfaction and does not vibrate, like it is out of balance, he should be good to go.
As for the 318/340 internals, it makes little sense to discuss unless you know what internals we are talking about. What does it matter if the OP drives it and it performs to his satisfaction and does not vibrate, like it is out of balance, he should be good to go.
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I think you're wrong on 67 being the only year the 318 had a forged crank. I have a 68 out in the garage that has a forged crank.
Dartswinger70
Well-Known Member
what they need is a good 318 piston that is 68-71 340 style high comp. I'm sure they may have 'em but then again maybe not...also is there an issue with a 2.02 X head valve hitting the cylinder wall? i really don't know I have 340s so never had to try and "convert" a 318 into something hot.
340sFastback
Well-Known Member
Found this one another thread around here:
Dartswinger70
Well-Known Member
so, it would appear that you really cant mish mash parts into a 318 unless you really know what you are doing.
mario03srt
Well-Known Member
Thats not what Uncle Tony says!
Never say never with Ma MOPAR. They used them in trucks later also, that is why I said cars. But if you buy a 1970 car 318 for a forged crank, you will most likely be disappointed.
mario03srt
Well-Known Member
Alrighty Then! So from this document of some origin (lol), looks like the 1970 340 internals swap into the 1970 318 is a good upgrade! Especially with some boost. Getting all of the casting numbers tomorrow after work. Thanks 340 s.
Good pistons for 318's are available. But at the end of the day you have to build to what octane gas you want to run. The only SBM that needs bore notches for 2.02 intake valves is the 273. 1.88 intake valve 340 and 360 heads work well on the smaller engines and flow almost as well as 2.02 intake valves. However it never hurts to check valve clearance at max lift plus a safety factor.
mario03srt
Well-Known Member
Well, the deal for the car fell through. Looking at a 416/340 stroked Dart w/ W2 Econo heads.
James Clews
Well-Known Member
I don't know about the USA but in Australia all truck 318s were 318-3 engines that had steel crank and fully floating piston pins but had the truck water heated inlet manifold and heads!
Dartswinger70
Well-Known Member
Thats not what Uncle Tony says!
318 340 cam 340 2.02 heads torker 650 carb headers 3.23sg g-60-14s 727 shift kit in a 68 dart 270 ran 14.4@96 mph
318 purple shaft 340 2.02 heads torker 650 dp headers 3.23sg g-60s 727 shift kit 125 shot of spray 68 dart 270 13.3 @104
318 340 heads 340 cam bolt ons around 280hp
318 purple shaft 340 2.02 heads torker 650 dp headers 3.23sg g-60s 727 shift kit 125 shot of spray 68 dart 270 13.3 @104
318 340 heads 340 cam bolt ons around 280hp
Dartswinger70
Well-Known Member
What's - e- maddah with the Torker? I see bad reviews on line but if someone put it on a stock engine like say a smog 318 or 360 I wouldn't expect much. I'd think with 10.1 compression and a cam it would do its thing at WOT at a 1/4 mile drag strip. I get there are better modern upgrade intakes but for a resto period correct build why does it get a bad rap?
its down on torque until 4000
3500 and up it works good
i always ran a single plane with spray and that was on most everything
not the current 100k mile bottom end 340 with the top end refreshed
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