I have 360 heads number 3418815 B, but can't find any info on them...

Author Topic: I have 360 heads number 3418815 B, but can't find any info on them...  (Read 4110 times)

Offline cudaracer

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So I think I stumbled on a good deal, a complete 73 340 engine from a Duster, that the guy wants gone out of his garage.  He has had it for many years, after rebuilding it into a 426 Hemi beauty.  The car had 33K miles when he pulled the motor several decades ago.  The story goes that the previous owner was trying to rebuild the 340, but gave up and sold it.  The block was machined +0.030" and looks to be ready, with 10.5:1 pistons. There is also the orginal 340 heads, plus what he called a set of 360 "performance heads" with the casting number of 3418815 A and B.  When I search the internet with those numbers, I can't find anything. What the hell are they and what year, etc.  They look in great shape and with the valves practically touching, I think they are the 2.02"/1.60" valves.  He also has original intake and a polished Al Weiand DP, original carter carb, 340 air cleaner, purple cam (although I don't know how to figure out which one), new dist with adjustability, polished 60amp Alt, 3 speed manual trans and a ton of odds and ends.  I am getting it all for $500. 

thoughts and information from questions above would be great.





Offline Bullitt-

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Re: I have 360 heads number 3418815 B, but can't find any info on them...
« Reply #1 on: September 26, 2013 - 11:21:09 PM »
Change that second 8 to a 9 and you possibly have T/A heads, you'd need the special rocker arms to work.
   look at 3418915....also listed for regular 340 & 360s 71-72

http://www.mymopar.com/headcastnumb.htm
« Last Edit: September 26, 2013 - 11:25:13 PM by Bullitt- »
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Offline cudaracer

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Re: I have 360 heads number 3418815 B, but can't find any info on them...
« Reply #2 on: September 27, 2013 - 12:12:13 AM »
the casting clearly says 3418815

There is no 9

I have a pic in front of me even.

Offline Chryco Psycho

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Re: I have 360 heads number 3418815 B, but can't find any info on them...
« Reply #3 on: September 27, 2013 - 07:59:34 AM »
it is an excellent deal for sure , I do not have my Speed pro books with all the casting #s but I agree that the 915 were the J heads or possibly T/A castings , the 10.5 compression could be difficult with todays fuels but Alum heads would fix that , & there are better heads to use like the Swirl 308 castings

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Offline cudaracer

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Re: I have 360 heads number 3418815 B, but can't find any info on them...
« Reply #4 on: September 27, 2013 - 08:58:04 AM »
OK, so after looking closer, it is definately a 915 casting.  Below is a pic of the head.  Can anyone tell me what size those valves are from the pic, or hopefully, if it is a TA head.



« Last Edit: September 27, 2013 - 08:59:58 AM by cudaracer »

Offline cudaracer

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Re: I have 360 heads number 3418815 B, but can't find any info on them...
« Reply #5 on: September 27, 2013 - 09:04:47 AM »
One other question regarding my build.  The pic below is of the 340 block, bored 0.030”, with pistons added.

My questions are, it is a 73 cast crank, and I am wondering if that is good enough for a 400hp build?
Also, he mentioned they were 12:1 pistons, but looking at them, they are flat with reliefs. They appear to be slightly in the bore, but with 66cc chambers, I seriously doubt they are 12:1.  Thoughts there too please.



Offline Chryco Psycho

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Re: I have 360 heads number 3418815 B, but can't find any info on them...
« Reply #6 on: September 27, 2013 - 11:25:21 PM »
2.02/1.60 valves J heads not T/A castings .

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Offline PlumCraZRT

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Re: I have 360 heads number 3418815 B, but can't find any info on them...
« Reply #7 on: November 04, 2013 - 01:22:33 PM »
One other question regarding my build.  The pic below is of the 340 block, bored 0.030”, with pistons added.

My questions are, it is a 73 cast crank, and I am wondering if that is good enough for a 400hp build?
Also, he mentioned they were 12:1 pistons, but looking at them, they are flat with reliefs. They appear to be slightly in the bore, but with 66cc chambers, I seriously doubt they are 12:1.  Thoughts there too please.

With a .039 head gasket (4.180 diameter), pistons .022in below the deck (1.800 compression height), and an overbore of .030, I calculate a 9.46:1 compression ratio.

EDIT: I forgot to add the overbore, which moves the compression ratio from 9.33 to 9.46.  After giving this more thought, I recalculated with the engine zero-decked and with no head gasket you still only get to 11.08 compression (with a .030 overbore).
« Last Edit: November 04, 2013 - 04:21:39 PM by PlumCraZRT »
mmmmm.... Mopar.... *drool*