340 TA with x heads ? or not

-
motobro

motobro

Well-Known Member
Joined
May 12, 2013
Messages
180
Reaction score
5
Location
california
I am looking at purchasing a 340 engine that supposedly has the "x" heads.
The block # is 2780930-340
Head # 2531894
vin on the motor LS23P9E123831.
I looked thru a few threads but it didnt answer my question.....are the heads the "x" heads ????
I know the motor is out of a 69 dart GTS, 340 w 275 horse according to the vin# decode.
 
x heads are not TA heads. Yes it should have an X near the spark plug hole in almost every case. 894 casting numbers.

Sounds like Jason's engine. He knows what's up and won't fill you with BS. Long time guy and straight shooter from what I know.
 
Is there a thread on the benefits of an "x" head.
Are they better than the J head?
 
If you are selling the x heads there will be a big benefit on your wallet over the J heads but it is my understanding there is not any or much difference at all between the two...
 
SleeperScamp said:
If you are selling the x heads there will be a big benefit on your wallet over the J heads but it is my understanding there is not any or much difference at all between the two...
Click to expand...

Not much except the X will have bigger valves than J in most cases.

When I was in highschool (1983) I pulled a set of J heads of a 71 360 state police highway cruiser and it did have 2.02 valves, dont know if it had been modified before it was wrecked but I scored good for 50 bucks.
 
Casting #2531894 {1968 thru 1971}

'X' Heads

mQaG-jST8IErBXhv58PEMcA.jpg


$(KGrHqNHJBMFICpGV(B6BSC7yrH2ow~~60_57.JPG

 
X head, schmecks head. There is NO advantage to the X head what-so-ever performance wise. If it is performance you are after, buy a J head with the 1.88 valves in it, install a 2.02 intake and do a PROPER seat and throat and you will have a better head than anything that came from the factory with a 2.02. The bowl hog crap they do to a head that comes with 2.02 valves from the factory cannot produce the results you can get from doing a correct seat, throat and bowl.
 
Agree,

The #2531984 'X' '340' Cylinder Heads from 1968 thru 1971 are just regular
'standard' 340 Performance Cylinder Heads.

The stock 'X' heads will flow at

Intake........ 205 CFM @ .400" Lift and 220 CFM @ .500" Lift.
Exhaust...... 135 CFM @ .400" Lift and 140 CFM @ .500" Lift
 
69 Cuda 440 said:
Agree,

The #2531984 'X' '340' Cylinder Heads from 1968 thru 1971 are just regular
'standard' 340 Performance Cylinder Heads.

The stock 'X' heads will flow at

Intake........ 205 CFM @ .400" Lift and 220 CFM @ .500" Lift.
Exhaust...... 135 CFM @ .400" Lift and 140 CFM @ .500" Lift
Click to expand...


Chrysler replaced the x head with the J head as a running change in 1970. But the J heads still had the 2.02 intakes through 71. There's not much difference between an X head and a J head with 2.02 intakes.
 
Correct Krazy Kuda,

No big difference in 'Flow' between the 'X' Head and 'J' Head.

#3418915 'J' Cylinder Head

The stock 'J' heads will flow at

Intake..... 205 CFM @ .400" Lift and 220 CFM @ .500" Lift
Exhaust... 145 CFM @ .400" Lift and 148 CFM @ .500" Lift
 
Didn't the j heads have hardened valve seats, as the x I understand did not.
I've had both, no noticeable difference. The chambers might have been a few cc smaller on the x.
It was nice sticking a 2.02 in a j head, as the valve sat up nice and high, unshrouding the valve for more flow than a sunken valve in a x head.
 
You must log in or register to reply here.
-

Back
Top