Porting the 200 head: Benefits, drawbacks, how-to, pics, etc

T

TucsonHooligan

Well-known member
Alright, before anyone says "do a search", I did, couldn't find what I needed, which is a rundown of how and why to port a 200 head. I have it at the machine shop right now to be cleaned and CC'ed prior to the block machining, but I will be getting it back so I can work on it.

I am a machinist (aerospace, CNC mostly, hence the farming out of the engine work to a pro) and can use a dremel and have an idea of how motors work ;) , but I need to know how to go about doing this, i.e., where to start, what needs to be done, etc. I have access to the proper tools, so all I need now is the advice on what to do. Plan for the motor is the 264/112 cam with a HW 5200 carb and a set of headers on a '66 200 from a Mustang to be put in my '64 Falcon. Let the arguing and nitpicking begin! Ask anything you want, I want to do this right the first time.

Also, what about aftermarket valves, tri-angle seats, etc. Is it worth the money and hassle for this motor, or is all that for racers and madmen? This is supposed to be a daily driver with a slightly enlarged pair of DNA silos. :shock:

Thanks!
Jim
 
There were some pics of a head that was sectioned so you could see how thick(or thin) the head is in some critical areas. I cant remember the title of the post, but it was pretty recent and I think it was in the small six section. Are you going to try to CNC it when nobody is looking(LOL).
 
Would love to CNC it but I have two major problems: 1. I work on lathes only and 2. I work for a major defense contractor that frowns upon (read: fires) people bringing in their own work. As many links as can be provided would be great, plus I'm interested to hear what people think about this. Is it worth the trouble and risk for the amount you gain? If so, what is that gain? I'm lookin for all the info I can get!
 
The pockets under the valves are the worst. They account for massive restriction and are one of the big limiting factors in improving performance. The cross section under the exhaust vavle is so badly cast that you can barely stick a finger into the port.

Cleaning up those areas will give you a significnat power gain. a bigger exhaust valve also helps, but finding one could be an issue. As a lather operator you should be able to cut down some small block valve heads and stems to fit if you don't want to buy new ones. A three or four angle valve job is worth the effort, too.

Keep in mind that all this stuff combined still gets you nowhere near the flow potential of the aluminum head.
 
I did a minor port and polish on my old log head. Nothing crazy, and really more of a polish with minor corrections to casting problems.

http://www.kastang.info/portpolish.html

Sure, it helps...but is it noticable? Hard to say as I did a cam swap at the same time. Nice part is it is free (minus the cost of grinding stones).

Slade
 
TucsonHooligan":3ewj5nzw said:
Would love to CNC it but I have two major problems: 1. I work on lathes only and 2. I work for a major defense contractor that frowns upon (read: fires) people bringing in their own work. As many links as can be provided would be great, plus I'm interested to hear what people think about this. Is it worth the trouble and risk for the amount you gain? If so, what is that gain? I'm lookin for all the info I can get!
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Jim,
Looks like you work at the same place I do! :shock:

Which machine shop is your motor at?
Porting the log head will have some benefit, no doubt, but nothing like bolting on the ClassicInlines alum. head will have.

Later,
Will
 
I have it at P.O. machine over in the Prince and Romero area. Done some work for me before on my '65 Lincoln, and I was happy with the quality and price. He seems to know his stuff. Would love to get that Aluminum head, but its a little cost-prohibitive, considering the head alone is 1400+, not to mention intake, carb, etc. So this is my best option, since daily driver is the goal.
 
TucsonHooligan":456w6xy7 said:
Would love to CNC it but I have two major problems: 1. I work on lathes only and 2. I work for a major defense contractor that frowns upon (read: fires) people bringing in their own work. As many links as can be provided would be great, plus I'm interested to hear what people think about this. Is it worth the trouble and risk for the amount you gain? If so, what is that gain? I'm lookin for all the info I can get!
Click to expand...
The gains to be had from a ported head are proportional to the mods you are doing to the engine. A moderately ported head on a stock engine will probably not yield much benefit, since the engines demand for additional air flow is not there. As you increase the demand in an engine for more air flow with larger camshafts and more compression and higher rpm, better exhaust and induction,etc... then a ported head will begin to show more benefits. Just like how all your parts need to compliment each other for maximum compatibility, the same is true for head porting. But starting with such a restrictive head, its doubtful anything you do will be in vain, and will only improve the head and performance potential of your engine!
 
Hey, I wasn't being critical of what he charges and, working in the machine industry, I am well aware of the cost of production on something like that. I am sure he is only turning a slight profit on it, considering the prototype costs and the fact that hes not building 100k of them. I merely stated that it was not cost effective for me at this time, so the passive-aggressive sarcasm is unnecessary.
 
Howdy Jim and All:

To answer your question, there is no down side to porting. Know that it is time intensive. It is worht the effort if you can do it yourself and you enjoy this kind of work. Focusing your efforts in the area about one inch either side of the valve seats will maximize your return. Valve size and seats are critical. Too large a valve face and valve shrouding negates any benefit. Given your cam, carb and intended use a 1.75" intake and 1.39" or 1.5" exhaust valve would be the best bang for the bucks. 1.5" valves are available from Azmike. A minimum of a three angle valve seat and backcutting the intakes is a must. The valves and valve seats will generate the greatest gain for a street engine like yours.

FYI- you may be money ahead to start with a D7 or newer casting. They will have 1.75" intake, a larger volume log, a larger diameter carb hole and Induction hardened valve seats to start with. The downside is that the chamber volumes will be larger than on your '66 head, but that can be compensated for by milling. 050" from the head.

In pocket porting focus on smoothing the transition from the cast surfaces to the machined surfaces, Rounding the short side bend, and reducing the size of the valve guide bosses.

Is it worth the hassle and the money? That's up to you. There are gains to be made.

Adios, David
 
TucsonHooligan":19avc5ue said:
Hey, I wasn't being critical of what he charges and, working in the machine industry, I am well aware of the cost of production on something like that. I am sure he is only turning a slight profit on it, considering the prototype costs and the fact that hes not building 100k of them. I merely stated that it was not cost effective for me at this time, so the passive-aggressive sarcasm is unnecessary.
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Wasn't really replying to your comments.
 
My topic. My comments. If you want to be snide, name names and direct comments accordingly, lest the originator think you're talking about him.
 
Thanks for the help guys.
Im all done with mine and its off to the machine shop Monday!!!
Took me about 9hr to get everything the way I like including the stock exhaust log.
I know the header would be better but its going on a all stock looking car.
 
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