How To:Basic Cylinder Head Porting for Beginners

I've been meaning to put this thread together for a few months now,since I had a conversation with a young HAMBer who had a lot of questions about how to do some porting work on his 289/302 Ford cylinder heads.

This isn't intended to be an advanced level lesson for professional racers,but more of just a quick and dirty guide to beginners who need a little direction so they can get started without turning a decent pair of heads into a doorstop!

Lets get started with what you're going to need to do the job:

First,you need your heads disassembled and thoroughly cleaned so you can get to work on them.
You can do this yourself with a valve spring compressor and a pressure washer,or you can just have your machine shop break them down and boil them in the hot tank,which does a much nicer job.

To begin,you'll need:

-Electric or pneumatic die grinder
-assortment of carbide bits
-mandrels and sanding rolls
-a light
-machinist's dy-kem or a red or blue permanent marker
-intake gasket
-exhaust gasket
-a scratch awl





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Ok let's go

 

I want to know everything you would like to teach. thank you

 

Then,use your marker or dykem to mark out the face of the the intake and exhaust ports:




The second picture didn't photograph real well,but you get the idea;the marking dye allows your scribed mark from the inside of the gaskets to be transferred to the face of the cylinder head surface ,providing a guide to shape your ports to....


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Suscribed. Please go on.

 

Then chuck your carbide bit up in the die grinder ( long shank bits will be necessary for some port work,but shorter ones work well for gasket matching and shaping the port mouth,and chamber work).

Carbides and sanding rolls are available from your local Speed Shop,Summit,Jegs,Speedway.

Start slow,and use gentle,steady motion on the cutter.Take your time and get the feel for it.

I like to rough in two sides of the port nice and close to the line,then flip the head over and get the other two sides....







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After roughing in the intake port to match your gasket,taper the shape gently,and not too severely back into the throat of the port.You can pull some material out of the pushrods bulge in the port,but don't get too crazy with it and break through.....
Then finish your intake port off with a chase with the sanding roll to smooth and contour everything,and set the final shape and contour,and remove any gouges,scratches,or imperfections...


Keep in mind,all this work was done very quickly in my garage this afternoon,just to rough things in and illustrate some of the methods used,and steps to take.


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Then,moving on to the exhaust side,repeat the process.....but on small Fords,the exhaust side is where you really earn your porting stripes...




See those two goofy looking lumps in the exhaust ports?Those are the thermactor bosses (closest to exhaust port)'and the valve guide boss (closest to the combustion chamber).

The thermactor boss is for the devil emissions control,present in Fords starting around '66 in California...It's a sort of air injection port in the exhaust.Dont look at me,I didn't invent this shit!

The guide boss really serves no purpose in a high performance motor.All it does is choke off the airflow and back up the port.
Removing it does nothing to harm strength or durability,but everything to improve performance.....


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Start by using your long shank carbide cutter to slowly work the thermactor bump out til the port roof looks something like this:




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Then continue using the same gentle,back and forth technique to get the cutter to steadily chew the exhaust guide boss out of the roof of the port.(The head is flipped upside down for these operations to provide easy access).







Finish up taking the port out to the gasket dimension,then smooth with a sanding roll....


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Now we can move to what's called the "bowl" area,directly under the valves.
We'll start with the intake:

The valve guide boss on this side doesn't have to be completely removed,but it needs to be pretty drastically streamlined and reduced in size,like this:







Just take it slow,and just glide the cutter very gently along the edge of the guide boss,slowly tapering and contouring it.I prefer to work one side at a time,but do what is easiest for you.

This is where having a variety of carbide cutters really pays off:For re shaping of ports,I like a non-tapered,cylindrical,round nose cutter.That makes keeping the walls nice and straight easier.
However,when contouring the valve guide bosses,a more oblong,narrow oval shaped bit is useful in getting into tight spots.

Also,make sure when all the heavy work is done,to smooth it all out,and shine 'er all up with a sanding roll,and don't forget to get the area directly under the valve seat,where that really awkward,rough transition from as-cast to machined meets....just be careful as always to stay away from the valve seats.


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Here's the transitional area I was talking about:








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And on the exhaust side:

Work the cutter into the bowl area gently and slowly to remove any gouges and ridges,and smooth out all roughness.


You don't have to take tons of material off,just make everything look more like the guy who designed the heads intended:No sharp edges,rough,casting lines,awkward corners to turn.
Instead it should be a smooth,flowing form from beginning to end,with some attention paid to slightly smoothing and reducing the angularity as the air and fuel has to turn the corner in the port.
This is what's known as working the "short side",or optimizing the "short turn radius".











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Finally,you can find a few more advanced horsepower in the combustion chamber if you get into larger valve sizes,by laying back the chamber walls to unshroud the valves,but I won't get into this.

Instead,I'll keep it fairly basic,starting with just cleaning up rough machine work around the valves:

View attachment 2128567

Careful,gentle application of the cutter here will buy you a bit of airflow just through smoothing things out so they play nice with the airflow.

Also,I was always taught by my crusty old porting mentor guy to smooth out the sharp edges in the chamber:

View attachment 2128568
View attachment 2128569
View attachment 2128570

Just knocking the edge off VERY gently with a carbide bit and following up with a sanding roll will do it.

Finally,I give the chamber the once over with the carbide bit very gently to remove any casting boogers,then polish it up real nice with a sanding roll,and call it a day.






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I know I definitely didn't cover everything,but I hope that I could be of help to the young guy who initially requested some information,or anybody else who's wanted to take a crack at porting their own heads,but may not have been able to get enough assistance or information to feel comfortable about it.
Thanks guys.

Scott


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What size gasket are you taking the intake up to ? 1262 ?

 

I normally use a 1262,because the 1250 is not much larger than the stock size.

The one I used in the pictures was a 1262R,because its all I had on hand.

I really like those Mr Gasket graphite ones for the exhaust though,both for decent port size,and durability.They can be reused a time or two,and they never seem to blow out.

Scott


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Nice thread. I did the exact same work to a pair of 289 heads on my "good" engine for my Fairlane. Everyone knows that you can buy a nice set of Dart heads for less money in the long run. It was good experience though to do a pair myself. I did it on a budget, one year I did the port work and added bronze guides and stainless chevy valves. Then another time I had them milled and added screw in studs. It was surprising how much e.t. it picked up as I did a little more each time. Hope you inspire someone else to start making metal shavings.

 

Great post, thanks.

 

Thanks Tommy!
The young guy who talked me into doing the thread was on a real tight budget,just like we all were at his age,and aftermarket stuff was not in the cards for him.

There is just something so cool,as you say,about taking your parts,and figuring out how to make regular stuff perform more like race parts than parts that fell off Grandma's sedan.
It's just an awesome feeling.Especially when you use those parts to put car lengths on a car that has the aftermarket stuff,but no tuning savvy




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Thanks Mike!

Scott


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Very informative! It's good to learn how to do things with less dollars and more sense. Thank you.

 

No problem!
I know it's not perfect,but it might help a guy get started

Scott


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Thanks powrshftr. Great tech!


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A BIG safety warning here. If you are going to use long-shank cutters in an electric grinder, make damn sure you use a speed reducer, or they can helicopter on you, which is NOT FUN.

 

It makes it SO much more fun when you do it yourself than just pay someone else to do it. Plus, you might just learn something.

 

THANX.... Great Info
LW

 

awesome, i got the itch for my FE...

 

Great thread! Thanks!!!


-LUKEY-

 

Great thread! How much HP can you add just by doing this?