lsjion ported head
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Joined: 10-06-05
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From: Seneca, South Carolina
dun dun dun..........
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Joined: 09-27-05
Posts: 231
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From: Portland. OR
CNC porting is derived from one good hand ported port, and duplicates it.
There is little variation from port to port.
Same can't be said for hand porting.
BTW....cylinder head gurus found out a long time ago that CFM isn't everything.
If this engine was more popular, someone would have a great CNC option.
Are there any such folks?
GM has changed the engine around so much.
These remind me a lot of the Quad 4 heads.
Tell me, isn't the LSJ head reasonably special? Better valves etc? I just wonder how many are around for rework.
Personally, my SS/SC is my driver, I don't have the down time to have it apart for more than a weekend.
Ron
There is little variation from port to port.
Same can't be said for hand porting.
BTW....cylinder head gurus found out a long time ago that CFM isn't everything.
If this engine was more popular, someone would have a great CNC option.
Are there any such folks?
GM has changed the engine around so much.
These remind me a lot of the Quad 4 heads.
Tell me, isn't the LSJ head reasonably special? Better valves etc? I just wonder how many are around for rework.
Personally, my SS/SC is my driver, I don't have the down time to have it apart for more than a weekend.
Ron
Last edited by RonSS; Nov 17, 2010 at 02:06 PM.
Senior Member
Joined: 10-06-05
Posts: 10,944
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From: Seneca, South Carolina
That's exactly what I was getting at. The point is that CNC is numbers inputed into a computer from someone else's hand porting. But usually it's zero or as close to zero variation from port to port. There are bigger gains to be had from a true hand port job rather than a generic CNC. The difference is you know exactly what you are getting from a CNC and a hand port you don't know till it's done.
Member
Joined: 09-27-05
Posts: 231
Likes: 2
From: Portland. OR
You are a sharp guy, I pay attention to your posts.
I am a drag racer, and I don't run an Ecotek engine......but I watch the BB Chev head progress very closely. Huge gains have been made.
My 5 y/o pump gas 496 makes 700 hp, and things have changed a lot since then. Ports have gotten smaller and flow more!
My point is, if a good head porter designs a port by hand, it can be duplicated by CNC. There should be no "generic" CNC job. What is that? Tweaked inlet and exh entrance and exit? The real magic happens in the chamber, the valve seats and bowl (short turn radius).
CNC can be used as a buzz word, sucks all the kids in, but if there is a head guru that has perfected a port design, both intake and exh for the Ecotek and transfered that to CNC, then it will be the cat's meow.
Until someone casts an aftermarket head and can CNC it to great HP gains (I haven't seen this) , well then we are left with CNC stock heads. And that may be great.
A great hand port would have to flow all ports, int and exh to get them the same. How much time would that take?
I would really like to have a stock SS/SC head to play with......I know enough to be dangerous, but simple tweaks can yield gains. One of my Quad 4 heads held an NHRA national record, until they killed the class.
Ron
I am a drag racer, and I don't run an Ecotek engine......but I watch the BB Chev head progress very closely. Huge gains have been made.
My 5 y/o pump gas 496 makes 700 hp, and things have changed a lot since then. Ports have gotten smaller and flow more!
My point is, if a good head porter designs a port by hand, it can be duplicated by CNC. There should be no "generic" CNC job. What is that? Tweaked inlet and exh entrance and exit? The real magic happens in the chamber, the valve seats and bowl (short turn radius).
CNC can be used as a buzz word, sucks all the kids in, but if there is a head guru that has perfected a port design, both intake and exh for the Ecotek and transfered that to CNC, then it will be the cat's meow.
Until someone casts an aftermarket head and can CNC it to great HP gains (I haven't seen this) , well then we are left with CNC stock heads. And that may be great.
A great hand port would have to flow all ports, int and exh to get them the same. How much time would that take?
I would really like to have a stock SS/SC head to play with......I know enough to be dangerous, but simple tweaks can yield gains. One of my Quad 4 heads held an NHRA national record, until they killed the class.
Ron
That's exactly what I was getting at. The point is that CNC is numbers inputed into a computer from someone else's hand porting. But usually it's zero or as close to zero variation from port to port. There are bigger gains to be had from a true hand port job rather than a generic CNC. The difference is you know exactly what you are getting from a CNC and a hand port you don't know till it's done.
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Joined: 12-31-06
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From: troy oh
Ralli, did you wver get stock flow numbers from the place that flowed your ported head? I've seen so many variances on stock flow numbers, which can really make a good flowing head seem amazing is percentages aren't shown
flowbeches are like chassie dynos they are good tuning tools and you get different results from different dynos and flowbenches sounds like the flowbench your head was done on was quite happy
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Joined: 12-31-06
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From: troy oh
https://www.cobaltss.net/forums/2-0l...61/index8.html
here is a link to some old numbers of mine, This was also on a smaller port and was unploished.
Just for comparison sake, the numbers shows a 30% increase from my stock numbers.
btw in qwiks post, he refers to me as bill, since it's my name on rlf
here is a link to some old numbers of mine, This was also on a smaller port and was unploished.
Just for comparison sake, the numbers shows a 30% increase from my stock numbers.
btw in qwiks post, he refers to me as bill, since it's my name on rlf
Last edited by lsjion; Nov 18, 2010 at 09:24 PM. Reason: Automerged Doublepost
Senior Member
Joined: 12-31-06
Posts: 686
Likes: 4
From: troy oh
here is the actual page link, I don't have the ability to edit for some reason.
https://www.cobaltss.net/forums/2-0l...61/index4.html
https://www.cobaltss.net/forums/2-0l...61/index4.html
