X heads

[Matt13]

What is a nice set going for these days?

[kawahonda]

Hard to say. Early J's are just as good as X's.

Depends on the buyer, and the seller. And the condition. A rebuilt-set that's ready to mount with receipt and work performed is always worth more. X sets that's been in storage collecting dust/rusting for the past 40 years in "unknown" shape is worth as much as scrap to me IMO.

What do you have, what condition would help us out more?

I'd imagine that "X" heads are worth the highest to those that are looking for date-coded perfection. So, smaller market.

[Matt13]

I'm trying to build my 1972 340 block to 68-70 specs.

[kawahonda]

Going to be harder that way. My Nov '69 1970 should have "X" heads, but they have J heads. They were rebuilt/replaced in the past. I went through the same logic process. Spend $800 on rusty overpriced heads + mucho-money on getting them finished/fittted, or just refresh my "J" heads. The choice for me is going to be simple, oddly considering being that I'm damned picky when it comes to originality of my engine...

Let me say of one story of me trying to buy X heads from a friend. He went up in his attic where they were stored for 30 years. Took pictures of what appeared to be rusty, stored "X" heads that were more than 12 months outside my date range. They were pulled of off a "racer's engine". It was a situation where the price I would pay would likely be the same as how much it would cost to get them fully vetted to go. Some think that the "X" head is a unicorn, but it simply isn't true from a performance perspective. Initially, but not really after release. Spending $2500 in factory heads just to get them ready to run at stock profile is a bit ridiculous, but the value of money is different between us all... 

At $2500, you'd be WAY under by simply buying some Engine-Quest iron heads with some mild porting that will kill "X" and "J" heads...like way under that.

The only difference between an early "J" ahead and an "X" head is basically that--the stamped lettering in a hard to see area. There's some really deep discussion via head experts on how the "J" heads may actually flow better in the end, but the differences are still super minor if anything performance wise. Like any head, they both cost craploads of money to fix. They also both cost craploads of money to modernize the performance some. How much is that "X" worth to you?

I guess where I'm going with this blabbering, is you may want to consider "J" along with "X" in your searches in your build if you want to save money, and still have what I (and likely most others) would consider original. Some out there believe that "J"s could have been date coded in '69, but I have still yet to see visual proof.  I know my "J" heads (dated in 1970) aren't original because they are blue, but they came with the car, they tell a story of the original owner when it was replaced way back when, and I'm way more happy to restore the heads and tell that same story to anyone who cares to ask. My car restored is way more special with the "J" heads....if you saw my engine pic you'd know...it was the only thing the original owner had to replace.

There's also that benefit of a later "J" head that have smaller valves that can be recut very cleanly to bring it up to early X and J heads. Think before you spend on this one.

[Matt13]

Well, I have two sets of J heads now. Both sets valves'  measure 2.02 and 1.60. I'm guessing the X heads will be the same? The guy only wants $300 for the X heads.

[kawahonda]

If they're in good of shape as your "J"s, I'd get 'em.....

[Fastmark]

$300 heads are cheap enough. It's the money you spend on any iron head that is the big drawback now. Good machine work cost money now days. I'd only use them if you need them for a date coded car. I've never gotten much money for any X head I've sold. You'll probably never sell them for a profit unless someone needs them for a restoration. I had a set not long ago that needed so much work, I gave them away.

[Rich G.]

I have a 340 sitting in my garage for years and it has 1 X head and 1 J head on it. I wonder how it ran? I never heard it run.

[HP2]

I've always left the X and J heads to the restoration crowd and used high swirl, non magnum heads from the 90s on my small blocks. Easily capable of 400 horsepower with  big valves and a bowl blend. Good port job can get them into the 450-475 hp range easily. Of course 20+ years after release, finding these may not be any easier these days.

[RUNCHARGER]

I think the swirls are better too if you can find a set. I have a set of X's or J's off my October 69 340 I should get rid of. I don't think I'll ever use them.

[Matt13]

I think the swirls are better too if you can find a set. I have a set of X's or J's off my October 69 340 I should get rid of. I don't think I'll ever use them.

I thought the swirl port were for 318's. I know they would fit a 340, but wouldn't the valves be a bit small?

[kawahonda]

They were on 89-91 360s. They should (or used to be according to others) be had for cheap if you find a set and are a superior head to "X" and "J" heads.

The 1.88 intake is not a big deal. It's likely still more performance. You can install the 2.02 larger valves if you wish. Easier to cut going upwards!

Ditto on the machine shop comment above....the amount you pay for heads is only the beginning, then there's the machining! An example is that I'm using Engine Quest Iron Heads on my 408 build. They are known for being cheap and offering lots of power. $700 for the bare heads, but another $1300-1400 for machining/assembled and bolt-on ready to spec with a port job.

[mopartaz]

Again I would get a set of (good) aluminum heads and be done with it. even if you got the x heads for free it would still be cheaper in the long run if you have to get a machine shop involved.
If you want the stock "look" just paint 'em.
Guy i know near Philly wanted $500 for his x  heads -used.

[HP2]

Mopar Performance offered several different high swirl iron heads off the shelf back in the '90s from stock to bowl blend to full out ported with stock or larger valves. They were a great value for the performance. Doubt you could find them today but there is other stuff available now.

There are several different aluminum heads with good flow numbers to all out race unit from $1200-$2000 a pair.

Indy offers their LAX and MAX iron heads for LA or Magnum engines.  These are nicely built iron heads for under a grand for the pair. I seem to recall Aero and someone else that slips my mind had an iron offerings that were reasonably priced.

I'd suggest you call a few local machine shops and ask for pricing on reconditioning heads and what that includes. Since your building a cruiser, you don't need to worry about hardened seats.  On top of the recondition price you'll also have valves, springs, retainers and seals. Add that amount on top of your purchase and hope your cores aren't cracked or damaged in a way that requires additional machine work. Then you know the total cost that may lead you to an alternative to X and J options.

[kawahonda]

Don't forget about engine quest heads too...solid price for solid performance!