gt40p head junkyard questions

Discussion in 'Fox 5.0 Mustang Tech' started by fivespeedsteed, Feb 22, 2013.

  1. so im going to go to the junkyard here soon and get some gt40 heads.

    my car is a great running one, 114k on the clock, dosent miss a beat, but leaks. the oil pan gasket is pushing out, rear main leaking (obviously) valve covers, ect. so the idea is to pull the motor, tear it down to a short block, spray bomb the bay, and start re assembling it slowly with all new gaskets, a mild (cheap) hci (since my goal for the car is to open track/auto x)

    im going to buy headers anyways, so i may as well spend the extra 40 bucks on frpp p headers, so i figure i may as well do p heads.

    ill grab the upper and lower intake and tbody while im in there too. i already have a 76 mil C&L and inlet tube

    the plan is a tfs1 cam probably so ill probably grab a tfs valve spring kit, get em milled and have the valve springs put in.ill probably also just gut my smog pump and block off all the passages for that. (visual inspection isnt too stiff here in va) ill probably keep the egr stuff if i can

    now my questions

    everyone says explorer, but mountaineer works fine too right? i know some late build 97s have them, and all of 98, but some say there are 99 and 00 p heads that are even better than the late 97-98 ones ? true? i know how to check the bars on the front and see if they are p's or not too

    also what is the consensus on what the best upper/lower intake combo is? any particular year explorer/mountaneer?

    what do i need to know about the internal egr system?
  2. The P heads will have 4 bars on the front of the head, vs. 3 bars for the regular 40's. Any of the 5.0 Explorer/Mountaineer intakes will work. Compare it to your stock intake and you will see were the #5 runner will need to be drilled and tapped for the sensor. The P heads do not use an internal EGR due to their improved design. The improved design allowed a cleaner burning mixture. The TFS cam is a good choice. Check your piston to valve clearance prior to milling them, so you know how much you can take off. If I remember right, about .030 will get you close to 10:1 compression on a stock bottom end.

    Good luck with it!

  3. so the egr stuff is easier to make work with the regular gt40s, not the p's?
  4. The earlier non-P heads and intake have the plug-n-play EGR system if you want to keep the EGR.
    If you do the P heads and intake, I am not sure how you keep the EGR, if at all. The parts don't have the internal plumbing/passages for the EGR.
  5. If you run P heads, plan on eliminating your EGR. The heads might be able to be drilled for the thermactor ports, but who honestly does that?

    There is no particular year "best" gt40p head, but keep in mind very early explorer/mountaineers may have had gt-40 heads and not 40p. Odds of finding these might be slim.

    When it comes to intakes, I prefer the early models. The lower intake part number suffix is -BA vs the -BB intake in later years. The BA intake is the same lower used on the ford gt-40 and cobra intake kit. It has a larger boss for the ACT and internal EGR (although with 40P heads...this won't matter) the later -BB intake does not have an act boss, so you might just have to tap the thinner runner.

    Biggest difference is the upper intake. The early explorer/mountaineer upper has thinking bolting flanges to where the upper bolts to the lower. Later intakes can sometimes have a mounting ear snap off. The vacuum routing is also a lot closer to that on a Mustang. But this isn't a big deal.

    My preferred shopping list.

    Pair of gt-40Ps.
    F6TE-xxx-BA lower intake
    F6 upper intake with internal EGR
    Throttle body

    I also plan on running the same setup with a TFS1 and crane cobra 1.7rrs. Consider springs on the 40ps mandatory.
  6. Sounds like Ps are not an option since he has inspection to worry about.
    No EGR = Failed inspection
  7. its just a visual im not sure the people around where i am are going to catch it with no egr stuff.

    so if i keep my egr i can still gut out my smog pump and kill that right?

    i plan on doing the valve sping upgrade to whatever i get.

    i thought you could run the stock 19 lb injectors with the swap?

    i found a 3g alt at the junkyard today, and i found a 96 mountaneer with the whole motor still there.

    so really if i wanted to pull from one car, and keep the egr system i need the heads/intake off a 96 (Non P)
  8. EGR and smog pump unrelated. EGR has no bearing on emmissions, but deleting it will cause a code that would cause an inspection fail because it would trip the light.

    Some GT-40s have the EGR ports and some do not. I think the truck gt-40s do not have it. I'm not 100% here so you'll need to do done googling.

    You can use your stock injectors, but the explorer 19s are rumored to have a better spray pattern. Either way, they sell for about $50 on good way to reduce costs if the yard will toss then in with the intake.

    Sent from my iPhone 4S using Tapatalk
  9. so basically i cant run p heads with my emissions stuff hooked up?
  10. Just make the 96 your donor.
    It has everything you need in a GT40 total package that will keep your EGR.
    It should also have the 'improved' injectors that still have the EV1 plugs that your car has. No need for adapters, and they are 19#.
    Make sure to get the 65mm TB also.
    Good luck!
  11. I believe the EGR system lowers cruising combustion temp and NOx levels. Otherwise, I would not have bothered keeping it on either recent Mustang. Wiki or google EGR and NOX for what it does. Something to read later
  12. I didn't read anywhere about whether you have Cats or not but if you remove the smog pump (thermactor system) you have to remove your catalytic converters or you will have problems.
  13. So make a 96 my donor? I can't do 96 intake manifolds and p heads?

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  14. The internal EGR is fed via the heads.
    I don't know for a fact, I have never had "P" heads, but I am told they don't have the internal passages to feed the EGR plumbing in the intake manifold. Check, if this is true, the answer to your question is "no".
  15. I bootlegged this from fiveohinfodotcom

    Differences between GT40 and GT40P?
    There are some differences between the GT40 and GT40P cylinder heads. First off, GT40 heads are equipped with thermactor holes to connect to the EGR/smog equipment. GT40P heads are not. GT40P cylinder heads use an external EGR connective system (I believe in combination with the intake manifold). However, the latter can be drilled and tapped to accomodate the EGR ports, if that is your preference. Secondly, the GT40P has a somewhat revised combustion chamber, and different spark plug placement. Because of this, not all headers clear GT40P heads. Make sure to use a known GT40P-specific header. Regular headers can be used, but then require different spark plug wires to be used, usually ones capped with 90° boots. Furthermore, there is said to be slightly different chamber volumes. GT40 combustion chambers are slightly larger, with volumes ranging from 63-66 cc. The Explorer/Mountaineer heads (GT40P) are somewhat smaller, measured between 58-61cc chamber volume. Thus, GT40P's may give a small bump in compression. Finally, the last difference between the two are valves. Both have 1.84" intake valves, but the GT40 has a 1.54" exhaust valve whilst the GT40P cylinder heads have a slightly smaller one, at 1.46".
  16. I have GT40P heads, F6 Explorer upper and lower, and TFS stage 1 cam. While my intake does have internal EGR ports, the P heads do not. My EGR valve is still hooked up to the spacer, but unplugged and non-functioning which always leaves my CEL on. We don't have emissions here, so that's something I don't know anything about.

    I picked up my heads already removed for $100. Went straight to the machine shop for milling, valve job, hot tanked and bead blasted, new guides, seals, locks, retainers, and Comp valve springs for $500. Some may think that's a lot of money to put into GT40 heads, but I have a $1000 in my whole top end including basically new heads ($600), Explorer intake ($50), new TFS cam ($179), barley used FRPP P headers off CL ($150) plus the new gaskets.
  17. So if I wanted to run P's and egr stuff is need the 96 explorer/mountaineer intakes and I'd be drilling and taping the heads? Is it a common tap size/ not too hard to do?

    Sent from my Galaxy Nexus using Tapatalk 2
  18. I wouldn't run Ps if I was keeping the EGR.
    Those holes are cast in with passages behind them, going straight to the exhaust ports.
    If there is no hole there, drilling isn't going to do anything without the internal passages cast into the structure of the head. It's not a straight shot, or anything you could add yourself with a drill bit.
  19. If you really want to keep the EGR, the p heads are not the answer.

    Sent from my iPhone 4S using Tapatalk
  20. how are the smog and egr un related? it looks like all the egr stuff is on the hose assembly by the passenger side header, and the main inlet for that is the smog pump?

    if i kept the egr stuff, i should just leave the smog pump stuff alone right?