340/360 Z heads? Anyone know what Z heads are?

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emnestor

emnestor

emnestor
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I have a 69 340 with Z heads. Large Zs stamped on them. I have never heard of them. Are they some weird 360 head??? Someo9ne earlier suggested they might be cop car heads.
 
all OEM small heads are basically the same..

J heads...O heads..U heads...Z heads..are all the same basic head....
 
83-86 offered a 318 4-bbl to the law enforcement community. Besides having a Rochester 4-bbl, the engine had 1.88 intake and 1.60 exhaust valves. The valves resided in a head with a honking 75.1 cc combustion chamber (casting # 4323345). This is known as the "Cop Car" head.
 
Thanks folks.
Can I safely say that these are 360 heads? Did the 340 block come with a Z casting ever?
 
70aarcuda said:
all OEM small heads are basically the same..

J heads...O heads..U heads...Z heads..are all the same basic head....
Click to expand...

This. Some day maybe somebody will start believin it. lol
 
2 Darts said:
83-86 offered a 318 4-bbl to the law enforcement community. Besides having a Rochester 4-bbl, the engine had 1.88 intake and 1.60 exhaust valves. The valves resided in a head with a honking 75.1 cc combustion chamber (casting # 4323345). This is known as the "Cop Car" head.
Click to expand...

I gotta pair of them on a 88 cop car motor.
 
4spdragtop said:
360 cop car heads (interceptor??) is what I have been told.
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i'm sure its just a wives tale (mith) from back in the day about them being a special head, there were "tons" of that floating around back then :-#, If you research, you'll see they were nothing more the a "police interceptor package", maybe a special cam shaft like an RV, 360 heads, exhaust (duals) & the QJ, special suspention for handling & higher rated tires for top speed & rain, The cop cars of the 80s were Diplomats, they were 318s, they handled very well & kicked butt, the cops loved them.
 
I have a set of 69 dated 915 casting # 202 valve Z heads that came off of a 340. They are the same as any other 202 valve 915 heads. They measure 68 cc. and im pretty sure they are a completely different head than the 83-86 "cop head"
 
Thanks swinger 340 . i guess I have come full circle. HMMMMM my engine is a 1969 340 and I would like to believe these are original 340 heads. Seems to be a lot of questions about Z heads. Thanks folks
 
70aarcuda said:
all OEM small heads are basically the same..

J heads...O heads..U heads...Z heads..are all the same basic head....
Click to expand...


This info is correct. These heads are all castings ending in 915. The Z was found on 1970 340's and were all 2.02 intake valves. as were O's. The J/U's actually U's cut off on some were 2.02 or 1.88 depending on the block casting. Z's were 1970 car, 1969 casting date motor. Z's 915 Were never found on cop cars or 360's unless someone put them on. The 4bbl 360 was not available until 1974 and these heads were long gone with 2.02. valves.

In all my years of working on these cars. And stripping them since 60's. I have only seen them or pulled them off of 4 spd scat pac darts . Not saying they were not on other models This is what I have seen them on. Heard of them being on Challengers from a friend bu I never saw them myself. Owned hundereds of Dusters and never saw them on a 70 plymouth. These are a rare find. Not anything different in the head from other 915's. But the casting letter Z is not a common thing to see.

I believe a limited production motor assembly. Sort of like the mount road test engines in 72. I only ever saw one 72 340 with the test decal on it. The rest were 318's saw plenty of them. I wish I would have kept that 340 valve cover now. To see if it was a 340 cover or off of a 318.
 
Very good reading and has the answer to all the cop car questions. (motors, suspensions, ect)
 

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Some guy around here was advertising mopar K heads. They were supposed to be from a 340. Anyone ever heard of them? From the picture it sure looks like the have a K stamped on them. Sorry don't have the casting number.
 
I myself never saw any through the years. but that doesn't mean there aren't any. I only can tell you what I saw over years of experience with 340 cars.
 
I bought a 340 from a guy last year that was a 1969 casting date. It had one X head and one Z head on it. Someone rebuilt the engine many years ago and swapped one of the heads. The guy I bought the motor from used to race his duster on occasion so it must have ran great.
 
74dusterman said:
I bought a 340 from a guy last year that was a 1969 casting date. It had one X head and one Z head on it. Someone rebuilt the engine many years ago and swapped one of the heads. The guy I bought the motor from used to race his duster on occasion so it must have ran great.
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Thats kinda ironic. I also pulled apart a 69 340 w one X and one Z head. The production date on the heads were only 6 days apart so I was unsure if someone had been there or if it was towards the end of the X heads and they just assembled it that way. My uncle has a 70 340 duster he bought new and it now only has 14K mi. on it. It has one O and one U head and that thing has never been apart for a fact. He drove it 2 yrs and its been on blocks, on carpet, covered up in a heated garage ever since. Paint and interior still like new. Ive been trying to buy it for years. Still has original tires. Off white car, w/ black stripe and blue interior. Auto on column w bench, w wheel covers. Kinda plain looking but that is how it came.
 
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