Need information on 340 J heads

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jeryst

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Guy I was talking to recently has a set of 340 J heads. Completely redone, tanked, magnafluxed, 3-angle valve job, painted. Everything installed and ready to bolt on. He wants $300 for them.

I'm not up on heads. What are "J" heads?
What questions should I ask?
What will they do for me?
Are they worth the price?
 
cuda20 said:
J heads are off a 360. I think they have 188 intake valve. ,160 exh.
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not so....72 and 73 340 have J heads with 1.88 intake...and 1971 340 are J heads...which would be 2.02
 
The letter head series. X,J,O,U etc... are factory iron heads that came on 340 and 360 engines. The only performance head is the T/A head and the early 340 head, both with 2.02/1.60 valves as stock equipment. A 2.02 can be added to any letter head or head there after.

In stock form, there fine at best for daily drivers and mild cam's added into the engine. Of course, other performance parts added on help, but, back to the head issue.

They flow on ethier side of 200 cfm on the intake.
They can be ported out quite well and flow up to 270 cfm, more is possible.
These heads are priced well and even better if the work is done right.
 
All letter heads flow within +-5% of each other and all can be had with 2.02's either by opening up their integral seats or by dropping new 2.02 hardened seats in. Purists will like the X's but they all are the same flow characteristics, even the T/A heads. T/A heads can be MADE to have larger intake ports by the offset pushrod hole, but they are the same casting, just final machined differently. 308's flow better out of the junkyard with a smaller valve with better port velocity.
 
still for 300.00 if they were done properly than it's a good deal.What are you putting them on?
 
If fresh, good machine work and you need a pair of heads, $300 is a good value.

A decent machinist in my area will get from 175-250 for a valve job alone.
 
that is a good deal i have O heads with 2.02 and spent 400 on just getting them re done.
 
bigdemo1 said:
still for 300.00 if they were done properly than it's a good deal.What are you putting them on?
Click to expand...

My 68 Dart has a built 360 in it, but I dont really know anything about what was done to it. It changed hands a couple of times, and that info was just kind of lost. I do know that it has headers, aftermarket intake, holly carb, a 3000 stall speed converter, electric fuel pump, and sounds pretty radical.

Guess I'll just have to start looking everything over and see what type of numbers I can find.

I saw these heads and just wondered if they were something special or not. The guy did not say what size valves were in them, and I didnt think to ask.
 
Do you have heads on the engine now?

Can you take a picture of the heads ports or know if there ported in anyway?

At the asking price, they could be worth picking up IF you want to use ported iron heads without down time on the engine/car. (Drive car while heads are being ported, install heads when there done.)
 
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