X-heads vs J-heads: what's the difference??

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Well then,

According to you, we should just throw this piece of garbage in the Dumpster.

This lousy foolish test instrument...........

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Watch that mouth, chebbie boy. lol


crackedback said:
Or if someone was putting a car back to original and wanted a correct piece.

Some of the data is hysterical. A T/A head flows more cfm than a J head with the same valve... that's a riot. It's the same port! Somehow it magically flows a significantly greater amount of air? If only it was so easy.

None of them work better than the other in stock form when outfitted in similar fashion. You just won't see it. One has a nicer intake and has hampered with a garbage exh port, another is more balanced. That's what was stated earlier in this 4 page diarrhea-fest.

These are the best posts in the thread:


What a space saver. More like Moparts every day around here.

I have to go out and work on my 78 Nova.
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skrews said:
tumblr_lq0x518Ly81qlzduwo1_500.gif
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LOL Only thing better than that GIF would be if it was two porta-potty pumper trucks. :)

The heads are so different that the assemblers didn't have much issue putting an X on one side and an O the other, a U and J, or O and U on a couple 70 340 cars we had.

Back to my Chevy!
 
Oh,

You mean the $6 Per Hour Engine Assemblers at the Chrysler Mound Road Engine Plant in Detroit.

Do you really think that anybody cared which Head went where on Friday afternoon in 1970......


Friday Night in Detroit at the Chrysler Engine Plant.........'This Bud's For You Crackedback'

th
 
69 Cuda 440 said:
You do know that Snake Plissken went both ways.
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He had to, because after servicing all the women on earth, he still had plenty left.
Still using that seat cushion? Snake want's to know...
 
Next thing you know, you'll be telling us how you have date coded air in your tires :)
 
This is what I got for $350. Bowl blend, pocket ported. More than good enough for what I want. 72cc, will need milling maybe. Reason I say maybe is because I bought them from someone else, when I take them in to be gone over I'll ask about then. So not sure exactly the final condition of them.
 

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Possibly closer to what the OP was asking; back in the late 80's my DD truck was a 78 W100 power wagon that came stock with a thermoquad equipped 360. When I got the truck it had a cracked head. I picked up a pair of heads locally for $150, cleaned them up and put the motor back together, and drove the truck for a few years. The motor lost compression on a few cyls , so I swapped the heads out for a pair I bought off a friend. I drove the truck for 3-4 more years then sold it to a friend. I even threw in the old heads I had taken off years earlier. Later the friend tells me that the heads were X and J heads. I was never able to tell any difference between the power the truck had with either set of heads on it. I raced other trucks in the mud and never lacked power with either set. Both were unported.
 
65cuda360 said:
Possibly closer to what the OP was asking; back in the late 80's my DD truck was a 78 W100 power wagon that came stock with a thermoquad equipped 360. When I got the truck it had a cracked head. I picked up a pair of heads locally for $150, cleaned them up and put the motor back together, and drove the truck for a few years. The motor lost compression on a few cyls , so I swapped the heads out for a pair I bought off a friend. I drove the truck for 3-4 more years then sold it to a friend. I even threw in the old heads I had taken off years earlier. Later the friend tells me that the heads were X and J heads. I was never able to tell any difference between the power the truck had with either set of heads on it. I raced other trucks in the mud and never lacked power with either set.
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Shhhhhhh

You're killing the fantasy. :)
 
Wait! which makes more power; X heads with worn out valve guides, or J heads with 1.88 valves????
 
Well, I ain't looking for a street monster. They're (X) good for what I want to do. They are better than stock 318 heads and I got them cheap. I'm no way near expert level, but I do know this much, I know when to ask for assistance.
 
69 Cuda 440 said:
I would say the 'X-Heads'.

Less Valve Stem-to-Guide Friction............:cheers:

But, only if your above 4000 RPM's.

What Do You Say 'Snake'....

th
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LOL, looks like he's been around for ever..
 
A young 'Snake' Plissken and Elvis discuss the differences between the 'X' Head and 'J' Head.

Elvis said he liked the 'J' Head, because of a slightly better flow at lower RPM's with a moderate-lift
Camshaft {for Street-Driven A-Body cars}.

'Snake' is about to drive his right foot in to Elvis' right ankle.

'Snake' says....................'X' marks the spot Elvis.


th
 
Followed by Elvis's poke in the eye for Snake...
 
Hey !!!! only one man gets to call me Pokey!!
 

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