picked up some x heads today..are they worth swapping

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gniknayrb18

gniknayrb18

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picked up some x heads with the casting number 2531894 05287 AAWJ340
the casting on the heads that i already have on the car are 3671587
 
ALSO....lol i know its early and im bored...what do you guys think of the way i have this thing set up. im new to the mopar game but i think this will work if not any suggestions.
currently
mopar 340
750 eddy
air-gap
comp cam 20-212-2 Advertised Duration 268/268, Lift .454/454
banged up headers
purple hornet glass packs
7 3/4 rear with 2.45
727 4 speed
hei dizzy setup
 
i knew about the gears but the cm was just put in when i bought it ..if i need another one what would you suggest
 
gniknayrb18 said:
and what are the differences of x heads and j heads and all that good jazz
Click to expand...
the only difference is the x head has a 2.02 intake valve . some say a j head with the 2.02 installed right has the advantage over the x .
 
gniknayrb18 said:
ALSO....lol i know its early and im bored...what do you guys think of the way i have this thing set up. im new to the mopar game but i think this will work if not any suggestions.
currently
mopar 340
750 eddy
air-gap
comp cam 20-212-2 Advertised Duration 268/268, Lift .454/454
banged up headers
purple hornet glass packs
7 3/4 rear with 2.45
727 3 speed
hei dizzy setup
Click to expand...

Fixed the trans for ya...is that a 8 3/4 rear or a 7 1/4 rear? If it is a 7 1/4 that would be the first thing I would get rid of...before you break it.
 
I agree if you have a 340, at the least an 8.25 rear is required.....
 
Unless your heads are worn (a.k.a. leaving valves) I don't think there would be much of a performance upgrade right now without a cam change. Could be wrong but I really don't think you'll feel any difference, maybe a tenth or two at the track.
 
The X heads will not perform better than the 587's you currently have. 587's are the same basic head as a 915J head. It's basically a swap that will provide no performance advantage. May even be backwards as the X heads have a really bad exhaust port.

I'd put more cam in it as well. The XE268H is probably the smallest cam I'd install from Comps line up. The voodoo 268 and bigger is another good choice in hyd cams.
 
wow i was tired this morning...it is a 727 3 speed with an 8.25 rear with 2.45 gears my bad guys. i picked those heads up for...$40 for the pair... it was either that or he was taking the to scrap yard...i hate to say this but i watched 3 complete 440's go and about 20 cranks hundreds of pistons i managed to grab 2 brand new sets of headers those heads and a couple of other things he just trashed
 
^^^ Man I hate when I hear about stuff like that, but then again thats how I pickup most of my cores.
 
Keep them on the shelf as spares, unless you're going to port them there's not really any advantage over what you're already running.
 
Leadfoot said:
In my opinion only. I would never dream of putting heads with forty five year old technology on my engine. I'd sell those X-Heads to someone that thought they needed X-Heads and sink the bucks into these.
http://www.hughesengines.com/Index/...el1=Q3lsaW5kZXIgSGVhZHMsIElyb24=&partid=25741
Click to expand...

$1000 difference in price there, buddy.

Also, age isn't the biggest factor in cylinder heads.

Take W2 heads for example, they've been around for about 30 years and they're still arguably the best cylinder heads that can be fitted onto a factory small block.
 
It's only some gaskets, etc to swap the heads if they are truly good to go. Make sure you've got the right springs on there. Who knows could have dual springs. May want to use your existing springs just to be safe. Coolant, headers, intake & your pretty much there.
 
Probably not going to see a difference putting those heads on. What size valves are on it? x heads came with 2.02 /1.60 early 1971 "J" heads are the same as X heads with 2.02 / 1.60 valves. The 72 and later 340 with J heads had smaller 1.88 intake valves
 
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