Ported X head pics

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X head castings are different than J. I also have a couple sets of virgin 2.02 J heads. I have not measured X head chambers, but you have to mill J heads .040 to get to NHRA minimum blueprint 64.7 cc chambers. J heads came out on 71 360's and were machined for 2.02 at the factory for 340's when they ran out of X heads.
 
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Jim Ward said:
It’s pretty well known on the 71 2.02 J heads I believe. However you can do some research to find more on them. J TA heads also had 2.02 valves. I know my 71 340 had OE head gaskets and was a standard bore and looked to have never been apart.

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Whats well known is that about 1% of the engines Chrysler built made the advertised compression ratio.
 
Dartswinger70 said:
LOL! you mean they were lower due to inconsistent combustion chamber volume...?
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No, the chambers were larger and relatively consistant. People take internet postings as fact, but us old timers who actually measured things and can remember how things were back in the day, can tell you the real deal if you care to listen. NHRA minimum chambers are not as cast, but the smallest chambers legal for "Stock" and "Super Stock" class racing. See post #26
 
Your X head probably flows a little better stock than a factory stock 71 2.02 J head. X’s are right about 200cfm with valves that are not sunk, they have a better short turn also, I think with just a gasket match, a little slimming of the guide and removing the guide tail that curves, good 11/32 stem valves / and valve job, minor bowl blending you would be at 225cfm enough for 450 HP.
 
The 894's I have are orig from my 69 cuda, so fall into the 68-71 category above.
I spoke to a respected machinist here on fabo and there are differences between the 2.02 J's and the X's.
I'll have to see what I can find for cutaway pics. Of course the templates I found dont cover the X's :BangHead: :mob::wtf:
Jim Ward said:
It’s pretty well known on the 71 2.02 J heads I believe. However you can do some research to find more on them. J TA heads also had 2.02 valves. I know my 71 340 had OE head gaskets and was a standard bore and looked to have never been apart.

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Thanks, new guides and vj are already done. What do you mean by "short turn"? Are you talking ssr?(floor) or a wall? I've read/heard, leave the floor alone and "raise the roof".
Do you think I can "pinch/thin" the guide boss in the pic where I'm pointing?

EL5DEMON340 said:
Your X head probably flows a little better stock than a factory stock 71 2.02 J head. X’s are right about 200cfm with valves that are not sunk, they have a better short turn also, I think with just a gasket match, a little slimming of the guide and removing the guide tail that curves, good 11/32 stem valves / and valve job, minor bowl blending you would be at 225cfm enough for 450 HP.
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4spdragtop said:
Thanks, new guides and vj are already done. What do you mean by "short turn"? Are you talking ssr?(floor) or a wall? I've read/heard, leave the floor alone and "raise the roof".
Do you think I can "pinch/thin" the guide boss in the pic where I'm pointing?



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Yes SSR, you can narrow it down there, the bigger problem is the tail that crosses over and the size of the guide itself. I’m not a expert but maybe someone else can chime in about the guide tail, and raising the roof
 
66fs said:
No, the chambers were larger and relatively consistant. People take internet postings as fact, but us old timers who actually measured things and can remember how things were back in the day, can tell you the real deal if you care to listen. NHRA minimum chambers are not as cast, but the smallest chambers legal for "Stock" and "Super Stock" class racing. See post #26
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4spdragtop said:
The 894's I have are orig from my 69 cuda, so fall into the 68-71 category above.
I spoke to a respected machinist here on fabo and there are differences between the 2.02 J's and the X's.
I'll have to see what I can find for cutaway pics. Of course the templates I found dont cover the X's :BangHead: :mob::wtf:
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Agreed there are differences from X to Js mainly the combustion chamber size from what i remember. I do think when people say they "flow the same" they are talking CFM in stock form. I would believe there are differences in the casting but have no evidence. Most just say they "flow the same". On another note what are you guys using to get castings clean? is it shot peening? I am also wondering who does this work at home vs a machine shop? I am interested in a Black and decker style valve seat refinishing kit . They are roughly 4-500 dollars, does anyone here refinish valve seats at home? or is it a machine shop only process? Alot of machine shops are drying up in my area so I am thinking it may be good to start rebuilding OEM style heads at home part time, who knows how it would pan out. May be a retirement gig like sharpening lawnmower blades LOL! For the record I took machine shop in tech school, I just never worked at a machine shop. There was more money to be made flat rate at the time as a line tech. I have a vague knowledge of how to check heads for wear etc and how to repair it. I say vague because I went to tech school almost 30 years ago LOL!
 
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I don't think there is, its a modified J casting a 915 casting. Looking at it they just filled the hole where the original pushrod would go, and drilled it over more so they could cast or port the intake port where the pushrod hole encroaches it. I may be totally wrong but that's what I see with the TA heads. If it were more than that it would have a whole unique casting number to itself right? Think in terms of a factory producing things on a budget.
 
i've done this Steve...just use your intake gasket and flop it to the head. You're not going to gain anything though and porting is pointless unless your cam is bigger than about .490 where the flow stalls out.
They will support 400 hp stock. I think the X, J, O, And '73's were all the same casting and were between 72 -74 cc's.The early 340's were rated at 63 cc's and 10.5:1 with X heads by the factory but that was so they could be milled to 63 cc's and be built to 10.5 :1 to be NHRA legal. I've cc'd a few and the smallest chamber i found was about 72 cc. Stock they were around 9.5:1 and that's right on the ragged edge for iron heads on the street...so watch it and watch out.
 
4spdragtop said:
Thanks for those! Are they TA heads? I know you're going 6 pack? I wonder if there is any difference other than the offset pushrod holes?
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No, just regular x-heads. Check out the pic of my ports, big pushrod hump. :(
 
I just posted a question on X-heads versus J-heads for my project and then saw this thread. Should've read this first.
 
Dartswinger70 said:
Agreed there are differences from X to Js mainly the combustion chamber size from what i remember. I do think when people say they "flow the same" they are talking CFM in stock form. I would believe there are differences in the casting but have no evidence. Most just say they "flow the same". On another note what are you guys using to get castings clean? is it shot peening? I am also wondering who does this work at home vs a machine shop? I am interested in a Black and decker style valve seat refinishing kit . They are roughly 4-500 dollars, does anyone here refinish valve seats at home? or is it a machine shop only process? Alot of machine shops are drying up in my area so I am thinking it may be good to start rebuilding OEM style heads at home part time, who knows how it would pan out. May be a retirement gig like sharpening lawnmower blades LOL! For the record I took machine shop in tech school, I just never worked at a machine shop. There was more money to be made flat rate at the time as a line tech. I have a vague knowledge of how to check heads for wear etc and how to repair it. I say vague because I went to tech school almost 30 years ago LOL!
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Chambers are similar, ports are better, X flow better (about 220 cfm) than 2.02 J (about 215 cfm) 1.88 heads (about 190 cfm and lower). Ask any "class" racer. You want to port them, then how good is your guy.
 
Yeah I cc'd mine and they averaged 70cc. I've already started(a while back) the gasket matching. I wanted to get chamber/bowl side done 1st then flip it and do the port side. Bad back, so less moving the better lol.
Heres link to cam, .495 lift
COMP Cams 20-247-4 COMP Cams Magnum Solid Camshafts | Summit Racing
ir3333 said:
i've done this Steve...just use your intake gasket and flop it to the head. You're not going to gain anything though and porting is pointless unless your cam is bigger than about .490 where the flow stalls out.
They will support 400 hp stock. I think the X, J, O, And '73's were all the same casting and were between 72 -74 cc's.The early 340's were rated at 63 cc's and 10.5:1 with X heads by the factory but that was so they could be milled to 63 cc's and be built to 10.5 :1 to be NHRA legal. I've cc'd a few and the smallest chamber i found was about 72 cc. Stock they were around 9.5:1 and that's right on the ragged edge for iron heads on the street...so watch it and watch out.
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Thanks for chiming in Bones, I have been trying to gather info for a while now. I get/understand the "secrets" with porting. I have spoken to @MOPAROFFICIAL on the phone and appreciate what he shares. I'm somewhat thickheaded and pics help me as much as words.
I figured a "wanted" thread might get more attn.
I know there were Mopar Performance templates for a variety of engines, but as of yet I havent found any for X or J heads.
All information I can find I will post here. I appreciate all the info found that others have posted.
In one thread @Cudafever posted cutaway pics of J's(I believe), so thanks for that! :thumbsup:
KCBones said:
I just posted a question on X-heads versus J-heads for my project and then saw this thread. Should've read this first.
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X heads have a slightly different shaped intake Port floor starting just before/at the hump /short turn.
Depending on what you're doing you can remove the guide bump or not... it can be utilized to a degree or flow limit to help direct...I guess you could call it.. the air from the roof. Imagine what the air is doing coming across that roof and hitting that bump. people talk about swirl ports and then we look at all of the ports themselves and they all look the same at the roof ..and the guide.. and the pinch and the bowl...and the only difference is the X heads longer flatter port of the ssr peak...then those closed chamber swirl port heads...
Well now could it be they are all swirl port in the sense of dog-legged humped on the straight side with a valve guide tail crossing over the roof to some degree.. would you gather the roof/common wall air goes straight down that steeper taller side on the straight and across the floor ssr and around the bowl ,on the dog leg side. Look at those trick flow heads and how they direct that dog leg side guide at the straight far side of the bowl... Ehh... who cares..right ;)
air doesn't have to always go down the path that was designed to.. if you completely reshape it or that guide and make the bowl & short turn right for it.. it will still flow a bunch of air. I wouldn't mind seeing some Dyno testing with the same head casting ported two different ways. Let somebody try and lay it back and do the stereotypical shape and let someone else exploit the original Port design.... .550 lift cam [email protected] 280 adv dur 106 cl 108 lsa...then a .550, [email protected] 280 dur, 109 cl 112 lsa
Rpm/vic 340 750 9.9comp & street headers. It's basically the crossover of high lift or low lift... but theres room for an edge.
 
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You can lay an x head back a ton more than a j head fwiw. J head hits water sooner in the ssr nearest the straight/common wall.
It looks similar to a laid back 318 short turn once in the 270's range. Hint.
thing is. .. if you dont know what you're doing you can damage the .200-.350 flow beyond what I'd call acceptable. Remembering that the valve job and throat size% is siamesely connected to the lower .100-.400 performance is important .
 
Them cutaways, i think were from the later "emission heads" All 340/360 head are basically the same. if your after max porting, every on says the X head will flow more because you can grind......in the right spots more. I haven't ported a X head to say.

Jim no disrespect, this just one mans opinion but. this is a good example of what NOT to do to a exhaust port. In my opinion, if you need to grind on the exhaust port you need a better head, and then still leave it alone. But, if you must, clean it up, only, and don't even clean the floor of the exhaust port Especially at the header flange area.
Just my 2c
Jim Ward said:
Not a ton of help I’m sure but these are the only two I have from my heads apparently.

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4spdragtop said:
https://www.bigblockmopar.nl/wp-content/uploads/2016/03/MoparPortingTemplates-RB_LA_Magnum.pdf
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Some one had a PDF file of them templets that was accurate and to size. There was some setting that you had to set your printer too to make them accurate......landscape i think. I was never Successful with a Quality printing of them.
Back in the day when you could buy the plastic W2 temples i bought them and then trimmed them to fit the hardened intake seat. That i had to have installed to save my head i had to have to save my head. Ported that port and then ground down the W2 templets until they fit my port. So that i could match all the rest or them.
That was long before i knew anything about a 88-91% bowl to seat ratio. these were 1.88 intake valve heads.
 
Many roll down the exit at the floor.
I've tried it. 2 reasons imo.
1. Typical 340 Headers immediately turn down...so are we flowing with headers used or just guessing what it ends up at.
2. The flow number goes up.
It's like tricking the port into thinking it has more floor radius than it has ..and that bump on the roof might be the diff of how well the rolling the floor exit works or doesnt. Not saying exh flow numbers are as important as a quiet port.
I don't think I'd leave the exh stock after porting the intake side.
Stock flow yields a exh flow ratio of near 75% @195-200cfm intake and 145 cfm exhaust....I'd still try for that.
Polishing, good.
Radiused seat work, even better.
You'll find laying the ssr of the x/J exh port can immediately shift the peak into the .700 lift with little effort.
If you play with the roof kink...try only removing maybe .030 and aim 'with' the floor. Remember its expanding as its moving past the valve..expand too fast will slow the air, the opposite of what we want in an exh port.
 
Thanks guys! Much appreciated. I'll be using the the Hipo Xhaust manifolds, so I'll chk to see how the exhaust ports match/mate to the heads. I know that an exhaust upgrade is in order, more $$ lol
When working on intake bowl and throat last night I tried an old stone I had and it "fit perfectly" or so it seemed lol, directly below and either side of guide. I think I'm pretty much done bowl side other than 80 grit for finishing(too smooth now I think). I'll mimic the other intakes to this one unless someone sees needed improvements?
Heres weapons of choice/destruction. I have a few of the long shank Chinesium burrs, but them pricks bend a little easier then what I thought. I'll shorten the shaft for better feel/control.
That rust spot on dog leg is right where the roof ramps up from port into bowl. I think I'll try to lay it back from port side.
Thanks again all :thumbsup:

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