Had my X heads ported - results

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512Stroker

512Stroker

We are all here because we are not all there.
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Just got my old LA 340 X heads back from a local retired engine builder.
I left the heads with him for some economy street performance porting as this is not a track engine. I had to remove the heads to swap out some bogus hyd roller lifters so I thought what the hell I'll have them cleaned up. These heads were prior used on a NHRA stock Eliminator LA 340 and had been acid ported. I also provided a new in the box Edelbrock AirGap intake that he touched up. The flow numbers shown below are through the intake and the head.
I would have liked to seen a little better exhaust numbers, but for $200 I'm not going to *****.
The Gent that did the work told me, which I agree, that its not so much the numbers but the shape of the port that really makes them work. Maybe when I get my back in better shape I'll post some pic's of the heads.
Jim K

Port1.jpg


Port2.jpg
 
$200?? You committed grand larceny! Definitely got you some heads that’d get you into the 11’s easily!:thumbsup: Care to give some details of what you’ll be doing with them?:)
 
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12many said:
$200?? You committed grand larceny! Definitely got you some heads that’d get you into the 11’s easily!:thumbsup: Care to give some details of what you’ll be doing with them?:)
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I felt guilty when I handed the money so I gave him a $ tip.
These heads will be going back on my pump gas 340 in my 67 Barracuda
10.5:1 compression
Comp XR274-10 cam on solid Morel rollers
AirGap intake with old 800cfm Edelbrock carb
Total custom FBO ignition system
TTI step full length headers

IMG_20180804_103808445_BURST000_COVER.jpg
 
"@.300-234 cfm"
"@.400-235 cfm"

With .100 inceease in lift and .7 cfm gain.

Aside from the .300#, yeah I'd love to see what the port floor looks like
 
Anyone in so cal wanna flow 2 of my heads? One Craigslist homebrew 976 (?) Casting and one J that looks pretty good. I'll buy the beer.
 
Well that does it I'm keeping every set of X heads I have!!! And big valve J heads also!!
 
Mtrhead said:
Well that does it I'm keeping every set of X heads I have!!! And big valve J heads also!!
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I always thought that the big valve factory heads had a fair potential for a serious street engine. Just look at the 10 second Stock Eliminater A body cars running iron heads.
 
davescuda said:
I think a stock X head flows around 180-190 on intake side.
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A set of good x heads cleaned up with a good valve job will go 220 on the intake.
I would be very happy with those numbers you may be on the edge of pump gas friendliness depending what's available in your area.
 
512Stroker said:
I always thought that the big valve factory heads had a fair potential for a serious street engine. Just look at the 10 second Stock Eliminater A body cars running iron heads.
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True Enough = The X's are clearly faster in our testing than the J's both with 2.02 Valves Probably enough to add 15 to 20 HP.
Those are VERY GOOD numbers
Be aware flow benches DO vary from one to another



Hint: Check out alignment of combustion chambers in J heads to block deck.
 
K.O. SWINGER said:
A set of good x heads cleaned up with a good valve job will go 220 on the intake.
I would be very happy with those numbers you may be on the edge of pump gas friendliness depending what's available in your area.
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We are fortunate to have a good supply of 93 octane here in MO.
Had a my distubutor custom curved for the build, no detention yet.
 
GTX JOHN said:
True Enough = The X's are clearly faster in our testing than the J's both with 2.02 Valves Probably enough to add 15 to 20 HP.
Those are VERY GOOD numbers
Be aware flow benches DO vary from one to another



Hint: Check out alignment of combustion chambers in J heads to block deck.
Click to expand...
This old Gent that flowed my heads probably treats his flow bench better than his ol'lady. LOL It's his baby. Flows everything at 28 inches
But to your point I agree there may be significant difference's between benches.
 
I had similar numbers out of my J's I ported. I wanna say they were 205ish at .300, for sure 243 at .400 then peaked at 255 from .500-.700. I needed more volume but at the time wasn't sure how to gain more. I bet the ports were wicked fast.
 
I would like to know what the acid porting did! Always been curious about that process. Did the ports look a certain way? What was the valve job like?

A S/E valve job has a LOT of science and skill behind it so these castings must have made the cut. If someone went to the trouble of acid porting those particular castings they must have showed better potential than the other 900 sets that were gone though before those were chosen.
 
512Stroker said:
I always thought that the big valve factory heads had a fair potential for a serious street engine. Just look at the 10 second Stock Eliminater A body cars running iron heads.
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I've long made the stock eliminator argument but usually get railroaded. lol It's a good and accurate comparison. Cars can go fast with factory stuff prepared right.
 
Those are some really nice numbers and even ore so for what you called the porting level.
Nothing wrong with a iron head and even better when you get them to work. Just so nice.
 
GTX JOHN said:
A Virgin Set of untouched X Heads suitable for stock elim. goes for $500. to $1,000.
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I know where there are a set of untouched big valve J heads just waiting to be put in service.
 
rmchrgr said:
I would like to know what the acid porting did! Always been curious about that process. Did the ports look a certain way? What was the valve job like?

A S/E valve job has a LOT of science and skill behind it so these castings must have made the cut. If someone went to the trouble of acid porting those particular castings they must have showed better potential than the other 900 sets that were gone though before those were chosen.
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Acid porting has fast become a lost art. NHRA engine builders have tight lips and the ones that know how to do head work dont give up their secrets. They produce 500 hp 340's that need to pass an NHRA tare down. The acid ported heads look like factory castings when done correctly. Most builders now use the NHRA approved special Edelbrock alloy heads, which are now becoming very hard to come by.
 
RustyRatRod said:
I've long made the stock eliminator argument but usually get railroaded. lol It's a good and accurate comparison. Cars can go fast with factory stuff prepared right.
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Not to get too much off topic but stocker combinations are really about sciencing out the entire car. Crazy lightweight tricks, big dollar converters and fully rollerized transmissions, 5.xx rear gear ratios, yada yada. The engine is a big part of the equation for sure and the heads certainly make up a large percentage of what makes power but as you likely know it's he whole combo that makes those cars so impressive. Nothing streetable about them espcially with bigger oil clearances. But to your point successful S/E engine programs are borderline pro level that are put together by guys with a ton of money and/or experience or both.

Like I alluded to, the heads that 512stroker ended up with could very well have been hand-picked out of many individual castings. In my mind stocker engine builders wouldn't just pick a random set of heads and give them the full work up, they try to find particular castings that show the most potential before any real work starts.

But yeah, being able to use aftermarket aluminum heads renders that whole process moot now. All the good factory castings are probably used up or gone now anyway so the switch to aluminum could have been borne out of necessity due to a forever dwindling supply of usable OE parts.

My point being though that your average A Body forum guy using them in a weekend warrior street machine type build up might not achieve the same results employing a similar methodology with a random pair of heads that someone left laying in the dirt for 40 years. And even if they could get them to perform really well, their car still may not work as well as a competitive stocker or an well-planned off the shelf combo with better flowing aftermarket heads.
 
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