Ford Muscle Cars Tech Forum banner

1 - 20 of 24 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter #1
Here are some pic's of my 66 289 heads that I have been working on, with the help from the people on this fourm. I think I may have went a little overboard with the exhaust runners by opening them up to 1.55" tall and 1.25" wide. Maby I will still have a little bit of lowend power. The valves were unshrouded by hand so im going to cc the chambers to make sure they are as close as possible. They were unshrouded for 1.94 intake and 1.6 exhaust, however the valves still need to be ground.


 

·
Premium Member
Joined
·
14,758 Posts
Wow, that looks great. I will add them to this post to the archives section where the other home porting pics are.
 

·
Registered
Joined
·
660 Posts
Nice work!

Unshrounding the valves by hand! I'm impressed!


You could lay the intake guide boss at a 45deg angle towards the runner. You still will have plenty to keep you valves in place...
 

·
Registered
Joined
·
7,470 Posts
Lookin' Good!

You might try widening the port floors as they approach the short turn. Narrow passages create high velocity, which will make the gases shoot right past the turn... disrupting the rest of the flow.

Widen the floors as much as practical before the short turn, but do not lower the floor.

A coarse cartridge roll on an extra long mandrel, or even an extra long carbide burr on low speed can be used. Just don't get in a hurry, and be careful.


Good Luck!
 

·
Registered
Joined
·
30 Posts
Discussion Starter #6
Thanks everyone,
I will try to widen the walls by the port floors as much as possable, Their seems to be plenty of metal still left in thies areas. I would also like to know what they flow at. When they are finished ill ship a head out to someone who can flow bench it. I have found several places over the Internet that can do it for around 75$. Ill let everyone know the results.
 

·
Registered
Joined
·
2,251 Posts
Flow both heads for 75.00 or just one cylinder? It coast me 200.00 to flow two cylinders (2 intake and 2 exhaust) on my 302 heads and that's why I'm building a flow bench. Let us know you make out.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #8
Its 75$ per hour and it usually takes 1 hour to flow 1 Intake and 1 Exhaust. I will also have the exhaust port with the heat crossover flowed too. Ill let everyone know the results, but that might be several months from now.

<font size=-1>[ This Message was edited by: Brian K. on 2/13/02 12:16am ]</font>
 

·
Registered
Joined
·
36 Posts
did you gasket match the intake to a fel pro 1262? I have a set of iron GT40's I'm porting and I just got the 1262 gasket and it's huge compared to the intake port size!

I have a weiand stealth intake that I'm using but it's already on the car and I don't know how big the ports are on it, anyone know if it's ok for me to open the intake up to the 1262?
 

·
Registered
Joined
·
30 Posts
Discussion Starter #11
I cant rember which gasket # it was, But it was a Felpro gasket. It was the only one that the local autoparts carred. So you can get an idea of the size the measurments are 2.05" tall and 1.175" wide. I have had no expearence with GT40 heads, but I can tell you should be carefull around the pushrod holes because thies areas are usually thin. Im sure someone ealse here can help you out a little better with your questions.
 

·
Registered
Joined
·
169 Posts
Is it possible to take too much off the exhaust roof? I took the EGR humps and valve guide boss down to the nothing... But now the roof is almost completly flat. Should I put a curve in it so it flows into the header a little better?
And how do you get that teardrop shape around the intake valve guide boss? I can't get my grinder into there at enough of an angle to get it to look like that.

I'll post some pics of my progress this weekend.
 

·
Registered
Joined
·
7,470 Posts
Is it possible to take too much off the exhaust roof? I took the EGR humps and valve guide boss down to the nothing... But now the roof is almost completly flat.

And how do you get that teardrop shape around the intake valve guide boss? I can't get my grinder into there at enough of an angle to get it to look like that.
The exhaust roof on my heads is flat. They seem to work pretty well.


The easiest way to streamline the intake guide boss if with an extra long burr or cartidge roll mandrel... from the port entry side of the port, not from the valve seat side.

Good Luck!
 

·
Registered
Joined
·
36 Posts
the fel pro 1262 gasket port sizes are:

1.28" X 2.10"

Anyone think that is too big for a weiand stealth intake manifold?

Thank you for the tip on being careful around the pushrod bump area, yeah it does look kinda thin. I guess I'll just open up to the gasket and make a nice gradual bend around the pushrod walls, hopefully this will make a nice venturi.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #15
To get the Intake guide boss into a teardrop shape I used a 6" carbide burr with a oval tip. The long shank gave me plenty of room to grind at diffrent angels going through the chamber side.
 

·
Registered
Joined
·
46 Posts
I am working on much the same project. I am doing a C8oe head though. Since one head was cracked I had it cut for cross section. I can tell you the bowls are about 2 tenths of an inch thick. I am currently doing this for practice and will then transfer the info I find to a different set of heads. I do have a little advantage as N2Omike was nice enough to send me one of his heads to look over in exchange for getting it flow benched for him. Mikes heads are a work of art.
I would just like to pass along a little info I have learned from my project. First is looking at your intake shoot is much like mine. Only I have holes in the roof from going to wide at the pushrod hole. The thing the camera shows though is how hard it is to keep things straight. I highly recommend a inside spring caliper and a dial caliper to make sure everthing is staying straight. The first set of heads I ever did I matched the intake port but by a 1/4" into the head it had tapered back to stock specs. Didn't do much good did it? Secondly is the width of the exhaust port. I think you are correct in saying the 1.25 is to wide, unless you are running a 1 3/4" header. I have been trying to locate tube dimensions at the port flange. The few I have found are much less than the 1.25 the 1415 fel pro gasket is. Having the head port wider than the header tube is going to give you no advantage. Not to mention the time you will save by not grinding out too far. My shop also told me to make sure the exit was smaller than the valve. going out that far is boredline at least. Essentially you want to do the opposite with the exhaust port as the intake. The smaller exit will increase velocity out of the valve. The last thing is probably more personal preference. I really don't like what you did with the combustion chamber. Reason being is you unshrouded the valves, but you left a straight wall for the air to hit. My shop could not stress enough when I picked my heads up about unshrouding the valves. What you do not want is the air to make a right turn to get past the valve and then another right turn when it hits the cylinder wall/combustion chamber. A smooth flow will be had by a gradual angle. So laying the chamber back would have been best. Taking as much material away as you have is also going to make you loose a bunch of compression unless you mill the heck out of the head. When you do that you are going to run into other problems like pushrod length and intake sealing. Trying to get those correct will cost you way more than the extra few cfm you likely have gained. I think the extra compression would have made up for the loss of flow from being a little more shrouded than you are now.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #17
I have a new picture of the exhaust runners after I reworked it from n2omikes advise. They look alot better. Ill try to post them sometime this week. In responce to jdsgallops post I apreaciate your oppions, I was looking for both good and bad thoughts on my port work. However I expect my chambers to be restored to around 58cc after the larger valves are installed and my heads are lightly milled. If my chambers volume comes out to be larger than 58cc their is also pistons and compressed gasket height to look at, which will also effect my final compression ratio. When I said I might have went overboard on the exhaust, I ment I might have made the volume of the end of the runner larger than the volume of the bowl area, which will cause it to out flow the seat and bowl area and stall the air flow. The same goes for the seat and bowl area, the bowl opening should be no larger than 85% of the seat opening. as far as my headers being too small I can always grind and weld on them, and if worst comes to worst I can make a set. Sorry for the long post ill try to get the pictures posted sometime this week.
 

·
Registered
Joined
·
660 Posts
Brian,

Expect your chamber size to be about the same or less than they were stock. It depends on how much you unshrouded and how high your new valves will sit in the chamber.

The first go around for me with unshrouding and a mill of .009 gave me a chamber volume of 51.5cc's !!!

I had the valves seats reground lower and the heads deshrouded again. I am know at 53.5 cc's

So just watch out... that CR can start climbing pretty fast!
 

·
Registered
Joined
·
46 Posts
Brian I guess if you start looking at aftermarket heads you will see that the chamber walls are always angled. A wall perpendicluar to the air flowing out the valve is going to make it stack up. Even with the walls out as far as you have them now I think this could still happen. By angling the wall you are going to direct the airflow down and away from the valve. My concern with how you have done it is not only this, but I know how much time it takes to do that and I have run into problems with milled heads before. I had a 289 that would break rocker arm studs for no reason, just tooling down the hwy and one would break. I did not have a large cam by any means in it. I went to a shorter pushrod and the problem was solved. Unfortunately those pushrods cost me almost $200. Then the intake wouldn't seal then there is more milling, meaning more money and down time. The less you take out of the chamber the less you have to mill and that means less possibility in needing other parts. A good example of this is the gt-40x head and the trick flow head. Look at both of there chambers. While looking at the trick flow also remember that those valves are rotated to get them away from the cylinder wall, yet the chamber wall is still layed back. If you happen to be lucky enough to have one of the 48cc chamber heads to start with then the milling won't be such an issue.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #20
Ok Here are the pictures of the revised exhaust ports. along with wideing the walls by the port floors, I also inlarged the walls and roof so that inside diameter is larger than port exit. Hopefully when I get them finished and flow tested the results will be good.
Sorry for the poor quality of the pictures they were taken with an older camera.

 
1 - 20 of 24 Posts
Top