I am getting ready to start doing some port work on a cracked head for practice before I do the ones I am going to put on my 400 that is going in my truck. I am looking for advice. I have looked at the heads and have some specific questions. It is pretty clear what to do in the exaust. Remove the emissions hump and clean the bowl then polish it really nice. I have heard that it is best to leave the short radius alone because there is water there. The intake is where I have questions. I am going to smooth the short radus because it seems to have a sharp corner with casting lines. Then there is a sort of ridge/lip where the machining for the valve seat starts. Should I smooth that out? I have also heared that doing a port match doesn't help much for a big torque motor like I am building (5000rpm max). Is this true from experience doing it and not doing it? I know most say it is good but I have heard from various sources that it isn't worth is. Anong those was a Muscle Mustang& Fast Ford article. And they support thier claim with boucoup data. Any comments? Any experiences would be VERY heplful.

 

Watch out for the water jacket hump in the exhaust port on some heads. The air injection hump can be removed.

Try here first,
http://www.sa-motorsports.com/diyport.htm
http://www.fordmuscle.com/archives/2000/07/homeporting/index.shtml

 

Here's some places to check out .. Lots of good reading
the last one is Chebby orinated.. but just think Ford and it will work too ..
And on the Kenny Moore page theres lots of things to ponder there.
That guy has way to much time on his hands, And a shop I wished I had.


http://www.sa-motorsports.com/diyport.htm

http://www.angelfire.com/ar/dw42/index.htm

http://members.tripod.com/lyc_42/km434/km434.htm

http://www.grapeaperacing.com/GrapeApeRacing/

 

In regards to gasket matching... I have read that it is next to impossible to actually perfectly match the intake/gasket/manifold. The imperfections cause some nasty flow disruptions. If you change gaskets or they shift slightly from the original position it leaves a portion of a gasket hanging out. You really want to avoid a small "shelf" anywhere on the intake port since it sets up a flow disruption. It is far better to have the manifold port slightly smaller than the gasket so that if the gasket moves around it will not protrude. The intake port should be at least as large as the gasket if not a little larger. This port "mismatch" actually flows better than even a perfectly "matched" port due to some arcane aerodynamic laws. The small step in the manifold surface actually helps intake reversion.

Just my 2 cents...

I have read all of the info in the above links and much more.

A Note About Gaskets:
-------------------------
Many gaskets are cut out using a ribbon die. Ribbon dies use a thin blade inserted into a laser cut groove in a block of special plywood. These dies do not last forever so new ones are made. The wooden base also expands and contracts with humidity. Other gaskets are cut with rolling metal dies that also expand and contract with temperature. The gasket material also shrinks and expands with humidity and age. All of these factors add up to the need for a little "fudge room" when it comes to matching your ports.

 

I'm glad you brought this up. It sounds like porting for dummies. When did the shape of the gasket become the ideal shape for an intake port. The only that does is slow velocity temporally. If the intake port is larger than the head, than I don't see any problem with matching ports. Use a gasket that matches the ports, not a port that fits the gasket.

If this is done on an Edelbrock Performer intake it's ruined.

See
"TIP: Edelbrock Performer Manifold. The Performer was not strictly built as a performance intake for the 2v. It was developed for the 2v crowd that wanted a 4v and the performance of chunking an iron intake for aluminum.

NOTE: After just purchasing the Edelbrock Performer for my 351C 2V, there is a SPECIAL INSTRUCTIONS section that is nice to know: The port size of the Performer 351-2V and the Performer 351-4V manifold was thoroughly researched and was designed smaller than the head port for several reasons. Although appearing small in size, the legs of this manifold not only flow more than the port in the head, but they also increase the flow in the head. The design of this manifold allows us to use great runner speed which prevents fuel dropout and gives us better fuel and air suspension. This combination is excellent for throttle response, total performance, and provides very favorable emission qualities. As a final note, please do not attempt to match the manifold to the ports. This will not only hurt performance, but it will upset many of the fine features that took months of research and development."

Personally, I think the 2V Performer uses ports that are too small for any serious power, but if I want bigger ports, I'll choose a different intake.

 

These are great links and tips. Thanks. And you are right, this is basic porting for dummies. This also renforces what I had heard about gasket matching. I am going to do minimal work on the intake track and spend my time on the exaust ports whick look pretty dismal. Are thier any pictures that anyone knows of of a well done exaust port? I am trying to figure out what to do around the valve guide and in the long raduis turn other than remove the emissions hump. There just looks like there is a lot of extra stuff there when you compare it to the intake ports. Thanks again for the help.

 

>The port size of the Performer 351-2V and the Performer 351-4V manifold was thoroughly researched and was designed smaller than the head port for several reasons. Although appearing small in size, the legs of this manifold not only flow more than the port in the head, but they also increase the flow in the head.
>

Sounds like Edelbrock has taken steps to remedy the gasket mis-match and intake "shelf" problem.

Nice to know, -Thanks!

 

My experiance with the Performer intake on clevelands (not 400's), is that it is no better than a factory cast iron intake. My experiance with it was using it as cast from edelbrock, (so I didnt screw it up by grinding on it), on a mild motor that was shifted at 5400 rpm (so it's not like it was a high rpm monster). On the dragstrip, it ran 13.80's in my street car (a 70 mustang). By changing intakes only, and going to a Weiand xcelerator, the car proceeded to run 13.20's, still shifting it at 5400 rpm. I think the runners are too small to get any decent power out of. The plenum might also be too small, but on my car, even adding an open spacer couldnt overcome the runners being too small.

On your heads, you can remove some material from the short turn without getting into the water. it is also helpful to widen it where ti transitions into the bowl area. The big hump around the valve guide can be knocked down some, (I knocked the corners off and made a much more gradual slope into the runner) without getting into the water (if there is any under there). I have been told there is water under it, and I have been told ther isnt but I dindt want to find out by taking too much off. I have a set of '76 "M" heads I ported, once I go back and get them, I will take a couple of pics and send them to you. Somehow I made better gains with them on the exhuast then on the intakes. I only got 225 cfm on the intkes ( that's horrible) but managed to get 180 cfm on the exhuast (thats as good as a stock 4v head flows).



Rob Hetzler
93 F150 Lightning, stock w/160k miles

69 mustang, 351c, 9.97 @ 134 mph
99 Pro ET track champion

 

The factory Cleveland 4V intake is hard to beat, just like the factory 4V 429/460 intakes. The problem is that there never was a 400 produced with a factory 4V intake so the Edelbrock or Weiand is your only choice to make that engine breathe. There is a method of machining the stock 2V manifold to fit a 4V carb that supposedly works. The machining would probably cost more than the aluminum E/W intakes do.

 

Which Cleveland Performer are you talking about? There were 3 made for the 351C.

My 400 performer worked very well. I don't know how much of the improvement was from the larger carb. I did a Performer cam swap at the same time.

They tested the stock 3514V/Boss against several aftermarket intakes in this build up article. 351/377C Dyno test.
http://stangstable.com/manifold.htm
The BT 4146 made 40 HP over stock.

The down side is cost. Around $350 for the BT intake, 351 4V iron intakes are cheap, and they require adapter plates ($??) to fit the 400.

 

[updated:LAST EDITED ON 08-Oct-02 AT 01:41 AM (EST)]Check out this site
www.sa-motorsports.com/diyguide.shtm
oopps already posted sorry