Easy replacement for stock cylinder heads

Discussion in 'Fox 5.0 Mustang Tech' started by GrandmasterK, Aug 10, 2011.


  1. GrandmasterK

    GrandmasterK Founding Member

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    I've got a 1989 Mustang GT with a blown head gasket. Since everything is going to be pulled apart anyways, it seemed like the perfect time to replace the heads too (not doing this myself).

    Ideally I'd like to spend under $1,000 for the heads (already spending more than that for the repair) and find something that can easily replace the stock heads without modifications needed to other parts of the engine. I know more about cars than many people but I don't know enough about this part of the engine to determine on my own which heads will suit my needs.

    Can anyone give me some good options? I've seen GT-40p ( or just GT-40??? ) heads thrown around a lot here, is that something that would easily work? I guess I'd have to get those from ebay though which I'm a tad leery about.
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  2. 2000xp8

    2000xp8 Mustang Master

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    Any head meant for a 302 can pretty much go on, you won't get the most of them without the supporting parts, but it's a good start. Used heads may say you some money.
    Look for gt40x and twisted wedges.
    I'd suggest afr 165's too, i just don't think you are going to find them in the $1000 dollar range.

    Gt40p's will require new headers.
    Gt40 irons (found on cobra mustangs and the oldest 5.0 explorers) don't.

    Still, if i had a grand to spend, i'd put it all in the heads. Others are going to say for a grand you can buy all the parts to do a cammed gt40p setup with intake, and it's true you can, but i'd rather lay a good foundation to build on with very good heads, than slap together a bunch of mediocre parts you are going to want to change later.

    Definitely go aluminum.
    #2
  3. wythors

    wythors Get off my lawn!!! Founding Member

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    GT40X heads can be found brand new for $1000-1100 quite easily.
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  4. GrandmasterK

    GrandmasterK Founding Member

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    Thanks for the suggestions! Are gt40x Ford Explorer heads as well? If I were to get these, I wouldn't need to buy any other hardware besides gaskets?

    For buying them, do you know of any reputable stores / websites that sell them or will I still being going through eBay?

    I'll definitely be spending the money on heads now... no other stuff for the moment. Since the old stock heads are coming off, now's the perfect time to replace them with something better.
    #4
  5. wythors

    wythors Get off my lawn!!! Founding Member

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    X heads are aluminum heads offered by Ford Racing Performance. Regular GT40 iron heads (often called "3-bar heads" because of the three bars cast into the end) are what came on the 5.0 Cobras and some Explorers. Explorer's also used GT40P heads which flowed basically the same, but had a different angle to the spark plugs which requires a specific header.

    GT40X heads can be found through all the major vendors. Mustang Parts & Accessories at 50resto is a site sponsor and a great supporter of the Mustang community. Summit Racing and American Muscle are two others that you can buy them from.
    #5
  6. GrandmasterK

    GrandmasterK Founding Member

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    Cool, I feel much better buying stuff from a website like that than eBay and I've bought a few items from them in the past. I see two models listed on that website for GT40X heads... looks like one has a 64CC combustion chamber and the other has a 58Cc combustion chamber... can someone enlighten me which would be better suited for my setup or give me an overview of what differences this will make?
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  7. wythors

    wythors Get off my lawn!!! Founding Member

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    If you have any plans for a supercharger or other forced induction in the future, go with the larger combustion chamber. If you plan to keep it naturally aspirated, either will work, but the 58cc heads will give you a little more compression. I have the larger heads on my convertible (more mods planned down the line) and am putting just under 300hp to the ground with other basic supporting mods. You can see what all I've done in my signature.
    #7
  8. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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    I'm a fan of the Trick Flow or AFR castings myself. You'll spend a little more than $1,000 on them though, but your potential power gains will be reflected in the price. Also, if you so decide to work the intake/cam ect later on down the road, the Trick Flow heads can be matched to their other components that normally come in kit form, and will give you proven, repeatable performance.

    If you can swing it....the complete head/cam/intake/rocker arm/timing chain, etc package will be far more rewarding...but the whole deal is going to cost you somewhere in the $2,500 range.
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  9. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    Heads can be had for the $1000 figure. BUT it's all the rest of the stuff that's going to eat your budget up. New heads mean that you need new rocker arms. You don't want to put the nice high performance heads on with the cheapo stamped steel rocker arms. There goes another $100 (used)-$300 (new) for some quality roller rocker arms. Hummm... Roller rocker arms - gotta check the valve train geometry to make sure the rocker tip roller is centered over the valve stem. Cough up another $12-$40 for an adjustable push rod and low tension test valve spring to make sure it is all set up correctly. If you go with Trick Flow heads, replacement rockers and push rods are a must, because the stock ones won't come anywhere near working – that’s $200 (used) - $500 (new). Total it up and you have $1400 - $1800 worth of goodies. That doesn't include the trip to the machine shop to make sure your used stuff is in good shape. That will eat up a good part of the savings from buying a set of used heads.

    Now that you have ruptured your dream about some shiny lightweight aluminum heads, think about reality. GT40 or GT40P heads are about the only thing left $200 - $350 by the time they get delivered to your door... But… right off the Explorer or someone else’s project means a trip to the machine shop to check for cracks, a valve job, knurl the valve guides, mill the heads, etc. Don't take the seller's word that "its all been done" unless he produces the paperwork to prove what comes out of his mouth! The machine shop work eats up $275-$350 for a top quality job. Going to turn some RPMS? Then plan on replacing the valve springs when you get the heads done - $100-$250. The GT40P heads flow better and have a better combustion chamber design, but require GT40P specific headers That another $150-$250 to get headers that will let you change the spark plugs. Add another $75 for spark plug wires with 90 degree boots and shorty spark plugs. Add another $50 for gaskets and miscellaneous parts and you are running $800- $1350 for the whole package
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  10. GrandmasterK

    GrandmasterK Founding Member

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    Thanks for the opinions everyone... Just when i think I can get heads and call it a day, I've got more to consider.

    I'm not going to get anything used, I'll go new all the way. I'd like heads but I don't want to get into replacing a ton of other things too. I'm supposed to meet with the guy doing my head gasket repair today and I'll talk to him about this some too and see what he thinks.
    #10
  11. skunk21

    skunk21 Active Member

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    jrichker always gives great advice on here. heads are one thing but don't stick the stock rocker arms and valve springs back on, they are weak. New haeds are going to require new rockers, a must do. A set of Trick flow heads isn't too far over a grand and set of rockers won't kill you either. easier to find a good used intake and pickup new heads, used intakes are all over the place. but again I don't think a new set of heads/rockers are far of your budget ( stay away from patriot heads, far way).
    #11
  12. WHT306

    WHT306 Member

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    $798.00 heads from tri state cylinder head we put a pair of 5.0x heads on my buddys 91 notch put them next to the gt40x heads another freind had laying around cant tell a difference in the design. they run good to stock bottom end ,b303 cam , performer efi intake and all the other boltons you usually do made 325hp at the wheels. best bang for the buck on a limited budget.
    #12
  13. Green 94 5.0

    Green 94 5.0 Founding Member

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    325hp to the wheels with a GT40X style head, B303, and Performer? I have to disagree there. I would say 290whp at best and that is assuming all of the other supporting mods are there to complete the combo.
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  14. WHT306

    WHT306 Member

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    OK 302,B303 CAM, PERFORMER INTAKE,5.0X HEADS ALL GASKET MATCHED, 31LB INJECTORS, 76MM MAF, 75MM T.B, 1 5/8 SHRTIES, U.D PULLIES, ELECTRIC FAN, NO AC, NO SMOG,1.6 ROLLER ROCKERS, SCT CHIP, MSD DIST& COIL & 6AL, 3 INCH X PIPE TO 3 INCH EXHAUST T THE BUMPER WITH MAGNAFLOW MUFFS, AND A T5 TRANS.

    So just because you have never seen it doesnt mean you cant put it to the ground.
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  15. Green 94 5.0

    Green 94 5.0 Founding Member

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    Well now it makes a bit more sense. You have a tune as well as removing all the drag off of the motor. You left those itty bitty details out.
    #15
  16. drexelsteve

    drexelsteve Member

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    Surf some dedicated drag racing forums, when some guys change classes they have to change their setup. I found a set of gt40x heads and everything to swap them in for 500. Heads were p&p, decked, etc and even came with gaskets and pushrods.
    #16
  17. Vinnietbird

    Vinnietbird Member

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    The "P" heads are really nice. I had mine ported with new springs and a good valve job. I also used my BBK shorty headers (unequal length). All I had to swap were the plug wires to a new set with 90degree plug boots. You don't have to buy new expensive headers to use them. It's a myth. The P heads are a great upgrade, and compared to the standard GT-40 heads, they are a lot cheaper, and actually a little better as well. They have slightly higher compression and a better (more efficient) plug angle. You can still use pedestal mount rockers as well, and they are a bolt on. I have them on my engine, and know they work great with no real effort other than the plug wires.
    #17
  18. 2000xp8

    2000xp8 Mustang Master

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    P heads $300
    valve job $200+ Port work unknown but you have to assume at least $200
    Headers $200
    Springs $150

    No offense, but to the average guy this just isn't sensible for a set of heads that are maxed out and made of iron and cost that much.
    And i assure you, it's not a myth that you need a set of p headers, unless of course you have tons of spare plug wires and like engine misses.

    P heads are a cheap bolt on and go head, but they aren't worth spending any extra money on.
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  19. Vinnietbird

    Vinnietbird Member

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    No, you don't need "P" headers, just 90 degree plug boots. It's not complicated. The heads can be found really cheap, and if the budget is really tight, just add new springs and use the P heads as they are. Still a great head. I have no misses or burnt wires. The engine has been for a year with no issues.
    #19
  20. 2000xp8

    2000xp8 Mustang Master

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    Vin, lets just say they do work (or at least for a while, nobody i know that drives alot has had it work for all that long), most good 90 wire sets are still around $100, not exactly cheap.
    And the make your own wires, i'd say they are unreliable at best.

    My point isn't that p's suck, my point is, don't invest too much in getting them on your car.
    #20

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