How much will taking out the exhaust port bump give me?

Discussion in 'Technical' started by scooper77515, Aug 25, 2005.

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  1. scooper77515

    scooper77515 No current projects.

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    Will I notice the difference if I just do the exhaust port bump? How much?

    If I do that, how much more would a crude (I have never done a port job) job benefit me?

    I don't want to spend more than a long afternoon, maybe a weekend, on this on stock 74 heads. If the benefits are negligible, I will just hold out and buy some aftermarket heads.
     
    scooper77515, Aug 25, 2005
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  2. scooper77515

    scooper77515 No current projects.

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    Also, are F7TE good heads? Local guy has them from a 98 Ford Explorer 5.0. Are these GT-40P?

    (Added afterwards in edit). Do you think this is a typo, and he means E7? I did a search on the forum for F7TE and only got this thread.
     
    Last edited: Aug 25, 2005
    scooper77515, Aug 25, 2005
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  3. bmcdaniel

    bmcdaniel Senile Member

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    If your gonna keep the heads for any length of time removing the bump is worthwhile. It works better if you also open up the runners and the valve pockets. But you won't complete all that in a few hours. If you have a couple hours to kill, take out the bumps, it can only help. And no, the car won't suddenly start nailing your eyeballs to the headrest just because you removed the bumps. E7 heads and GT40Ps are two different animals.
     
    bmcdaniel, Aug 25, 2005
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  4. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    Yes, it's worth getting that area cleaned up. That bump is a left over in the casting from the days of the air pumps. When I do a simple gasket match porting job, it takes about 8 hours of work. Polish up the exhaust side as best you can and leave the intake side rough - big and rough is good for intakes. Reason not to polish the intake side is roughness helps mix the gasoline and air in a street engine. Just one of the many little things that can be done to tweek a SBF.
     
    Acornridgeman, Aug 25, 2005
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  5. scooper77515

    scooper77515 No current projects.

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    Acorn, that is the kind of job I was thinking of for a weekend project. I have heard that the stock heads are not too bad, relatively speaking, on intake, but horrible on exhaust, so I thought I would open the exhaust a little. I have never done heads, but figured it couldn't hurt, since I am not doing any deep grinding, and don't expect to hit any water ports.

    So the secret is to buy new exhaust manifold/header gaskets and grind the holes open to match?

    Also, I don't have headers yet, so a major head job will not benefit me right now.

    Would attaching new headers to the heads, then installing the heads be an easier way to install headers? Would that take care of some of the "lifting the engine" issues involved with header installation?

    If so, I might buy headers before reinstalling the heads.
     
    scooper77515, Aug 25, 2005
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  6. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    I'll get some picture for you later tonight. I have a set of heads that are raw and a set I just finished. Stick to the gasket match and stay away from doing any major work in the bowl area and you will have no trouble with water passages.

    later
    Eric J
     
    Acornridgeman, Aug 25, 2005
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  7. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    OK - here are some pictures. This is one head that is completed and ready to bolt on and one head that is fresh from the junkyard. In a gasket match porting job, what you are trying to do is get rid of the major imperfections in the casting that mass productions heads all have. First, clean the head and get it ready for marking. What you want to do is lay out the gasket into place on the head and scribe a line around the inside of the gasket opening. I use Prussian Blue lay out ink and a metal scribe. Once you have all the mark up done, you can go to town on the metal inside the scribe lines with your air grinder (die grinder) and proper metal cutting bit. Cast iron is tough on bits. I can make one $4 bit last for one complete head. After the metal cutting bit work, I use a Dremel tool with the little sanding barrels to smooth and polish as needed. After all work is done, clean them up and get ready for assembly or further machining. I gasket match the intake manifold as well. It takes me about 8 hours to do a set on heads.


    Good luck,
    Eric J

    (PS - working on iron heads is almost an art form in my book - take your time and enjoy it!)
     
    Acornridgeman, Aug 25, 2005
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  8. stmanser

    stmanser Looking for a Maverick

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    i did mine recently and i can feel a difference but i cant notice anyting on the track....it has better throttle response...and i can hear it a little better...

    other than that...maybe in the right conditions it might have helped...breathing in a car is always better than choking...

    if i could have bought new heads i would have..i couldnt afford them so when i had to take the heads off anyways...i went ahead and ported them....removing heads just to port....probably not needed
     
    stmanser, Aug 25, 2005
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  9. ratio411

    ratio411 Member

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    Port match the first .25" of the intakes.
    Then grind out the bump in the exhaust.
    If you want to go futher, work done on the top of the exhaust port is worth FAR more than on the lower part of the port.
    Also, exhaust flows better with a smooth surface, so polishing the exhaust side is okay.
    You can smooth the bowls and take out a bit of the exhaust guide without hurting anything.
    Dave
     
    ratio411, Aug 25, 2005
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  10. scooper77515

    scooper77515 No current projects.

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    I have a Performer 289 intake, I know, I bought the wrong one!, but can I do similar to it...gasket matching and removing a little material? Never paid attention to it when I put it together, so it may already be opened up, since Edelbrock is pretty good at what they do.
     
    scooper77515, Aug 26, 2005
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  11. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    I have done aluminum aftermarket manifolds a little bit. Just to clean them up and make a nice even match with the head. Do the same thing by holding the gasket in place and see how much extra material is there. I was mostly referring to factory type cast iron intakes in the post. They often need work to get a nice even fit.
     
    Acornridgeman, Aug 26, 2005
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  12. scooper77515

    scooper77515 No current projects.

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    OK, I bought some gt40p heads today, pretty clean, off a 98 Explorer. I want to do the gasket match port on both intake and exhaust. Do I only go in 1/4" on these also? Is it a grind 1/4" into the holes, at a 90 degree angle to the faces?

    I will use the barrel sanders to clean and polish as much as I can reach on the exhaust side.
     
    scooper77515, Aug 26, 2005
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  13. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    From about 1/4" to 1/2" depending on casting shapes and defects. Every head is a little different. Once you start, you will get a feel for it pretty quick. You are just trying to make a nice clean fit that will flow smoothly. Take your time, you will pick up the feel for it quickly.
     
    Acornridgeman, Aug 26, 2005
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  14. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

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    Here is a flash picture - you can see how deep I was - about 3/8" or so on average.


    Eric J
     
    Acornridgeman, Aug 26, 2005
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  15. scooper77515

    scooper77515 No current projects.

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    So you are just angling the hole into the port, not 90 degrees into it?

    I have a picture of my port with the gasket taped on on another thread http://mmb.maverick.to/showthread.php?t=17875

    Do I take an oval port and grind it square, or did I get the wrong gasket?

    I wonder if I should wait and see what port shape the headers will have before I start grinding...I would hate to go from a big square hole to a small round exhaust pipe.

    One of the header companies I talked to today said their headers had oval ports.
     
    scooper77515, Aug 26, 2005
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