340 identification

Besides the numbers on the block is there any other way to tell if it's a 340 or a 318?
The Duster i just got is supposed to be a 340 but there is so much oil and dirt on the numbers on the block above the starter i can't read them.
It has a 2 barrel intake on it but it could have been changed for some reason,and i'm not sure of the difference between 340 and 318 manifolds.

Any help would be appreciated. :)

You could check head casting numbers. Just pull a valve cover. May give you a better idea.

What year is the Duster? Most likely a '72 and '73 would have a "For 340 cast crank only" small counterweighted balancer.

Original engine paint could also provide a hint. But I'm not sure of the exact years and color changes. I believe 340's started out orange in the late '60's and went to blue somewhere in the early '70s'. Red sticks in my head for 318's. :scratch:

If the engine is suppose to be original, check the VIN. The 5th digit would be "H" for a 340 and "G" for a 318. If the car has anything smaller than an 8 3/4" rear or a 904 trans, it was likely a 318 car.

But comparing head casting #'s is a very good indicator!

The Duster is a 71 but i already know it's an original 318 car,but the guy i bought from said that the guy he bought it from told him that it was replaced a while back with a 71 340.
The engine paint is blue i'm not sure if it's the factory paint though.

What will the casting numbers on the heads be if it is a 340?
I have a 69 340 in my Scamp but i really don't want to pull the valve cover off of it just to check the numbers.

The #s on the block just below the head on front drivers side will tell you. Will even tell what day it was put together. Hope it is a 340. Ray

Thanks Ray,i'll have to check there. :D

Evil all 340's built after April 71 wore Blue paint. If the thing is a 340, and has the factory intaKE MANIFOLD, IT WILL WEAR A CASTING NUMBER OF 3512100. The heads would be J stamped for 71 if corect motor. I'll try to find the correct 340 casting numbers for you as well. Hope this help.

Hate to say it, but the heads will not identify if it is a 340. Its hard to find a 30 year old motor that hasn't bean altered or rebuilt. My 340 has 360 heads. Best bet grab a small wire brush and a can of degreaser. Not fun, but it won't take that long. And best of all you will know for sure. Maybe you have a 360 in there!

If the engine was a 360, then the balancer would, or at least should, show it to be a 360.

If the engine was a 360, then the balancer would, or at least should, show it to be a 360.

I allways thought this to be true also, but recently I was told that is wrong because later 340 and 318 blocks withs cast cranks also have a 360 type balancer.

DUDE, AWESOME AVATAR yOU CHECK THE #'S ON THAT BLOCK YET EVIL? Who hit my caps lock button? :drunken:

DUDE, AWESOME AVATAR yOU CHECK THE #'S ON THAT BLOCK YET EVIL? Who hit my caps lock button? :drunken:

I have an extra one of an ok looking chick with a hot body dancing kinda sleasy if you want for your avatar.

coool lets give it a try

ok than get on yahoo and I give you what you need.

cool it worked Thanks dude!

I must be getting old. That's neither o.k. nor hot, border line sleazy. Yep, just checked, I'm old. Ray

If the engine was a 360, then the balancer would, or at least should, show it to be a 360.

I allways thought this to be true also, but recently I was told that is wrong because later 340 and 318 blocks withs cast cranks also have a 360 type balancer.

Nope! 360 had a big, smooth counterweight cast into the balancer, cast crank 340 had a small counterweight with "For 340 cast crank only" (or something like that) cast right into it and 318's were always flat, with no counterweights regardless of crank material, just like the forged crank 340's. Later "original design" 360 cast cranks had material taken out of the opposite side of the balancer face to compensate and I'm not sure about the Magnums. The 360 Magnums had less offset weight than the original 360's and probably had weight removed instead of added to the balancer.

I thought so. I didn't think what the guy was telling me sounded right but I am more familar with the 360 than the other 2 LA eninge's so I took his word for it.

Hey is that Locomotion car yours? I think I saw it in one of last month's mopar mags.

Mopardude,

:hello2: Yes, that's my car and the pic you saw was in the Jan. '05 issue of Mopar Muscle. Bruce Biegler does a good job covering a variety of Mopar race results for them. I've had the "Locomotion" name on my Mopars for over 25 years and use to bracket race a Challenger.

.......but I get my subscriptions later than most and I always find out from somebody else when a pic pops up somewhere! :sad2: :dontknow: :tongue:

Cool!

So what is that dancing chick saying??? I usually like blondes, but she'll do.

I dunno! I prefer woman with some tits but she seems pretty flexible so I would give her a twirl.

So are the balancers off a forged crank 318, such as a 69 or 70 the same as the early 340's? What year did they begin using the cast crank on the 340? 71 or 72?

Forged AND cast crank 318 balancers can be interchanged with forged crank 340 balancers.

1972 is suppose to be the first year of the 340 cast crank. But there have been several engines that showed up in '72 cars that had forged cranks - early production cars that used leftover parts!

I forgot I knew that about the 318 balancers. Thanks. I have two "'71" 340's lying around and both have forged cranks in them. I am almost sure they were both in '72 cars, but I haven't verified this by the VIN yet.

my original 340 out of the demon also has the forged crank. I also have a extra crank and pistons out of a 69 motor. Any difference in the 2? I know the earlier 340 s had the higher compression ratio.

looks like she is saying i like it up the $%^%

Hey gts, you have a couple pics of your cars?

Yeah, I have some pictures, but not ones I can post yet. I've been thinking of doing this. The only decent looking one is one of my B5 Swingers. Someday I'll get some taken with the digital camera and get to posting them.

I think your letting your imagination work too hard. The girl is saying " :shock: I love it when GTS340 spanks my sweet ^$$!".

Well i finally got chance to check the numbers on the so called 340,and it's kinda what i figured it's a 318 :x
Oh well,at least i got the taillight panel i needed for mine and another A-body 8.75 rear and some other odds and ends.

I find that a lot when looking at older cars and trucks. If it has a V-8 most people will try to tell you its either a 340 or 360. Most of the time I think it is just because they don't know. If I can prove its a 318 than I allways try to get them to drop the price between $200-$500 depending on the vehicle. Good thing that hasn't worked for me yet other wise I would have a crap load of 318's laying around.