Help with identifying engine

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Nidhögg

Nidhögg

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Hello,
I picked up a 340 engine today, and would like to know a little bit more about it.
I was told it was a '73 with 360 heads.
The numbers I found on it is:
GM 340P 35480045
2780930-340-6
1 21 71
Also got a big 4 stamped on it.

The numbers on the header is:
3418623
6 16 71

Is there any way to check the heads without taking them off?
I will open the engine and check to see what needs changing, but like a boy on christmas I want to know what I have right now, not sometime next week :p

I am a little bit unsure about the year on the engine, so I have attached a picture.
It does say 71, right?
Also, the engine is red, the 72´s are blue if I got it right?

MbUTQiWl.jpg
MbUTQiWl.jpg
 
I would say that is a 71 model year block. Either the last half of 71, or the first part of 72. Look at the passenger side of the block just above the oil pan in front there is a pad with 8 digits on it. Post that number and we can tell for sure what model year car it was in.
 
Nidhögg;1970327021 said:
Is there any way to check the heads without taking them off?
[/IMG]
Click to expand...


Yes. Pull off the valve covers and maybe the rocker arms. Look for a casting number on one of the ports on the head. You can look up the casting numbers to tell what heads you have.


Also look around near the spark plugs for to see if they have any letters, like a "J".
 
EDIT: Nvm, I found the number: 1B367245

There is the letter J by the sparkplugs, and a mirrored J on the other side
 
No, go to the block on the passenger side of the block where the oil filter goesj (that is the rear of the block). Then look toward the front of the block just above where the oil pan, there is a flat spot with 8 digits. There will be a number, then a letter, then six more numbers.

That will tell for sure what model year car this came out of.

I am leaning toward a 71 model as the GM 340P
means that it was built for premium fuel. 71 had 10.5 compression, in 72 it dropped to 8.5.
 
71 it is. Also 71 would have been orange, not red. Its obviously been painted. Good motor none the less....
 
krazykuda said:
The original engine in my 71 Challenger 340 convertible was blue.
Click to expand...

I scratched a little on the digits to see the numbers more clearly, and exposed some blue paint beneath...
I think I recall the guy I bought the engine from saying that the engine has been in a Barracuda, don´t know if it was that cars original engine or not tho.

Anyway, the number is 1B367245 and it´s J heads, will try to remove the covers tomorrow and see from the numbers if it´s 340 or 360 heads.
 
Your good, my 72' 340 Roadrunner engine says 340R, for really slow, as compared to my 68' 340. (just kidding guys!)
 
Nidhögg;1970327121 said:
I scratched a little on the digits to see the numbers more clearly, and exposed some blue paint beneath...
I think I recall the guy I bought the engine from saying that the engine has been in a Barracuda, don´t know if it was that cars original engine or not tho.

Anyway, the number is 1B367245 and it´s J heads, will try to remove the covers tomorrow and see from the numbers if it´s 340 or 360 heads.
Click to expand...

Awesome! You have a 71 340 engine!

Is it still all original? If it is, then you have all the good stuff:

Forged Crank
Cast 10.5 pistons
J heads and X heads are the best stock heads that came on a 340 (besides T/A - special production heads). They should have 2.02" intakes for the '71 engine versus 1.88" for the 72. The 72 engine only had 8.5 compression.

Does it still have the original intake? Many people like those for thermoquad carbs. Is the thermoquad still on the engine?


You have a great engine to start with!!!!


Ps. If it still has the original head gaskets, please measure the thickness and let me know. I'm interested in how thick the factory 71 340 head gasket was.
 
Thursday, April 15,1971 build date. 45th one built on the day.
The heads are only going to tell you casting # with valve cover off, but if they did in fact come off a 360, should have 1.88" intake valve. Even if they were original J heads for that engine, with 2.02" intakes you wouldn't be able to tell without pulling them off. Should have a forged crank, and your harmonic damper will indicate that, the cast damper says "use with cast 340 crank only" and has an offset counterweight cast into it.
 
With the P designation it should be the 10.5, big valve, forged crank engine. The cast crank engines were low compression and didn't require high octane fuel thus no P in the assembly stamping.

G = 1971
M = Mount Road engine assembly plant
340
P = premium fuel (high compression engine)
3548 = as said - Thursday April 15 1971
0045 = 45th engine built that day
 
71beater said:
Thursday, April 15,1971 build date. 45th one built on the day.
The heads are only going to tell you casting # with valve cover off, but if they did in fact come off a 360, should have 1.88" intake valve. Even if they were original J heads for that engine, with 2.02" intakes you wouldn't be able to tell without pulling them off. Should have a forged crank, and your harmonic damper will indicate that, the cast damper says "use with cast 340 crank only" and has an offset counterweight cast into it.
Click to expand...

No, I found out that the J heads were used on 340's in 1971 with 2.02" valves. Had me worried when I saw J heads on my first 71 340. Then I ound out that they had changed over to the J head and used the 2.02" intake valves during the end of 71. I was about to accuse the machine shop of pulling the old switcheroo on me....

Just put a scale up to the valve. If it is slightly smaller than 2", they are 1.88", if it is a little bigger or even with 2", then they are 2.02" intake valves. J heads did come from the factory with 2.02" intakes.
 
Not arguing, re-read his post. He was told heads are 1973, off a 360. Yes, it's possible they are original (to this engine) 2.02, or later 1.88. Let's not forget, it's also almost 43 years old, who knows what's in there without opening it up...
 
Or...maybe I mis-read...
Either way, there is no way to know if those heads were original to that engine.
 
krazykuda said:
Awesome! You have a 71 340 engine!

Is it still all original? If it is, then you have all the good stuff:

Forged Crank
Cast 10.5 pistons
J heads and X heads are the best stock heads that came on a 340 (besides T/A - special production heads). They should have 2.02" intakes for the '71 engine versus 1.88" for the 72. The 72 engine only had 8.5 compression.

Does it still have the original intake? Many people like those for thermoquad carbs. Is the thermoquad still on the engine?


You have a great engine to start with!!!!


Ps. If it still has the original head gaskets, please measure the thickness and let me know. I'm interested in how thick the factory 71 340 head gasket was.
Click to expand...

Well, I was expecting a '73 engine, so, I´m thrilled right now :D

I can´t say 100% that it is original, but I know it´s been sitting in the corner of a garage since at least 1981...
If I remember correctly (at work now) it had the intake, don´t know if it is the original or not. Best way to look it up?
No carb on it, also missing one side exhaust manifold.

Since it has been sitting since 1981 I would assume it´s the original head gaskets, I will measure them when I start picking the engine apart.

71beater said:
Not arguing, re-read his post. He was told heads are 1973, off a 360. Yes, it's possible they are original (to this engine) 2.02, or later 1.88. Let's not forget, it's also almost 43 years old, who knows what's in there without opening it up...
Click to expand...

I was told it was an 1973 engine, with 360 heads of unknown origin.
I will post the numbers when I get them off :)
 
krazykuda said:
The original engine in my 71 Challenger 340 convertible was blue.
Click to expand...
Must have been a late 71 model when they started to swap colors? I know 69 is screwed up, seen 69s red, turquoise, and orange depending on when car rolled out, or plant
 
Nidhögg;1970327579 said:
If I remember correctly (at work now) it had the intake, don´t know if it is the original or not. Best way to look it up?
Click to expand...

Here's a link to the casting numbers for the intake manfolds. The original intake will be a cast iron spread bore intake. Many people think that the 71 340 intake is the best stock spread bore intake the factory put on them.

http://www.mymopar.com/index.php?pid=69
 
Anyway, the number is 1B367245 and it´s J heads, will try to remove the covers tomorrow and see from the numbers if it´s 340 or 360 heads.
Click to expand...

If you look you may see something along the lines of AAWJ 360 cast into the heads. This doesn't mean they're 360 heads. That throws a lot of people off. Look at the casting number on the #1 intake runner. It should be along the lines of 3418915 or 2531894. Keep in mind that the 2531894 is unique to the 340 through 71 and was not used on the 360. The other one 3418915 is not unique to either engine as it was used on both the 340 starting in 72 and the 360.
 
3418915 started being used on 340's during 1970 model year. They were the primary head used on 1970 340's.
 
Alright, so, I looked at the number on the heads now:
3418915

So, that means it could be either one of the 340 and 360 heads?

Also, I took a picture of the intake.
Notice the different colors on the head covers, one red and one blue.
I checked both heads, same number.
Is it the original, good, intake?

gDgiCIxl.jpg

gDgiCIx
 
Yes, that looks like it is the original intake.

Yes, someone did change the left (driver's) valve cover. That one looks like someone put a 67 or 68 right side valve cover on it because it has the "brackets" for the wire harness.

Your right side valve cover is probably the original one. It also has "tabs" for the wiring harness.


I have an original 318 out of a 71 Challenger Convertible, I could take a picture of the valve covers if you need to see what they looked like that year. I believe that the 318 & 340 used the same valve covers that year. Just say the word. You may just need to find an original left side valve cover to make it original again.

Your original '71 intake is the most desired intake for the thermoquad fans that like to run spreadbores. They say that it is the best factory intake for spreadbores. Unique to '71 only.


There's another guy from Sweeden on here that just posted about getting a Holley street avenger carb. You two should meet if you are close enough.

Here's that thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=266066


And another one from a young gun (18 year old) in Sweeden also:

http://www.forabodiesonly.com/mopar/showthread.php?t=266523
 
The previous owner has a set of M/T valve covers that I can get, if I can get a set of Ford (I think) covers for his car.. So for the moment I´m hoping I can get those instead :)

Will look up the other guy and see where he lives :)
 
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