1971 plymouth 340

[gclintonmopars]

What was the last year the X was put on the 340 heads Thanks Gary.

 

[oldkimmer]

..............1971 was factory installed.......kim....

 

[mopartom340]

My late build 71 has J heads.

 

[crackedback]

1970 and early in the year.

A 71 with X heads being factory installed is a long shot. 915J style head was the "production" head for most of the 1970 model year and on.

 

[Locomotion]

http://www.mymopar.com/headcastnumb.htm

 

[jimmer]

I have a 72 that has O heads same as X
The build date is 71 but in a 72 car also has a steel crank .

 

[jimmer]

I have heard that Dodge / Plymouth used whatever they had left over , so some cars had parts from prior years installed ?

 

[Oldmanmopar]

I have early 71 demon one J 915 one X 894 All original car bought it from 1st owner. I will install matching J 915's. Have seen 70's with X's , O's and Z's 894's and 915's combined. There are U's that look to be J's do to being cut off by the plug hole. I hae here one set of 915, 188 valve and 915 202 valve they have different port size and ramp. 188 is a lot smaller bowl's. and some that are same. Heads are not always matching sets so beware of what you are buying.