Anyone running GT40P heads w/ 1.7rr & HO cam?

Discussion in '94-95 5.0 - Specific' started by DavidBoren, Feb 20, 2015.

  1. DavidBoren

    DavidBoren Active Member

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    As the title states, I am inquiring about first hand knowledge of GT40P heads with 1.7 roller rockers and a HO cam on a stock GT short block. I am aware that new springs would be needed to accommodate the lift. Just curious as to what kind of performance this combination yields on an otherwise stock set-up.

    If you are using or have use this combo, please post your impressions, driveability, dyno info, and intake/tb/maf size /info, as well, please.
     
  2. Firefighter181

    Firefighter181 Active Member

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    Well I cannot give you a specific answer on this combination yet, I will be able to in about 2 months.

    I have a set of GT-40P's w/TFS springs, COMP/FRPP 1.7 rr's, new push rods, and FRPP "P" headers that will be going on end of April. Motor currently has 65mm TB, Stock MAF, 19's (I plan to keep the stock injectors), Edelbrock RPM intake, SN95 elbow, catless x-pipe, and MAC Flowpath x-back.

    I will be sticking to the stock HO cam for drive ability concerns. Again sorry it is not real world data as of yet however Ill keep you posted.
     
  3. 5-oh-MUSTANG

    5-oh-MUSTANG Well-Known Member

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    Out of curiosity im also considering a gt40 top end swap, how much hp approx. would u be making with ur setup?
     
  4. Caboose302

    Caboose302 Well-Known Member

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    What intake are you planning on running? My 95 had GT40P heads, Trick Flow Street Heat intake, E303 cam, 1.7rr, 70mm TB and put down 273 I believe. I'll gave the dyno sheet to the new owner.
     
  5. RichV

    RichV Well-Known Member

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    Without a cam, GT40 heads/intake, OE TB, pulleys, stock exhaust manifolds, MAC prochamber H, was 240 or so rwhp.

    Same setup with E303 cam and shorty headers bumps to 260-270rwhp.
     
  6. 5.0l cory

    5.0l cory Member

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    I am going to do the same thing to gt40 p heads to swap with 1.7 rockers stock cam injectors explorer gt40 intake i already have a 70mm tb on with a cold air intake. just like to know if i will be making more power or not. sorry to jump in:eek:
     
  7. DavidBoren

    DavidBoren Active Member

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    Thanks for the replies, so far. I look forward to hearing about your real world data once you get set up.

    What I want to do is build an n/a 302w for use in my daughter's daily driver. And here is what I'm thinking:

    1999 Explorer engine ("P" heads and EDIS),
    Cobra 1.7rr/intake/throttle body/MAF/injectors,
    HO cam,
    Coil on plug conversion,
    Gear drive timing kit,
    ARP everything,
    Long tube headers,
    And, if they will work with the "P" heads/1.7rr combo, I would like to hunt down some pre-'86 flat-top pistons to bump up my compression ratio. I'm just not sure if the flat-top pistons would interfere with the valves while using 1.7 roller rockers, considering the GT40P's already have smaller combustion chambers. But I would like to see a 10.2:1-10.5:1 compression ratio with the engine still being non-interference. And, if I can find one for a price I'm willing to pay, I would like to use the tubular intake, just for sh!ts and grins, make my daughter's car special sort of thing.
     
  8. RichV

    RichV Well-Known Member

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    The 86 pistons and GT40 heads are like russian roulette. There are guys that say they've done it, there are also guys that have bent valves with E7 heads and 86 pistons. Cam and lift is obviously crucial.

    That said, I'll swap you a set of 86 pistons for a set of fly-cut. Standard bore.
     
  9. Keith5.0

    Keith5.0 New Member

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    GT40 heads and intake with E303 cam, I left stock springs and rockers in heads and just had them cleaned up, 24lb injectors and MAF and the car made 248 to the wheel... would like to know if the rockers make that much of a difference but doesn't matter now as I am going Performer heads with 1.6 Rollers soon.
    Car has all the bolt ons save for the pulleys.
     
  10. 99GreenStang

    99GreenStang Active Member

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    My advice to you is get some aluminum heads. Yeah it may seem expensive, but I have firsthand experience with GT40P heads.

    I rebuilt the heads replaced springs, retainers, seals, locks etc. along with the purchase price of the heads I could have got a VERY cheap set of aluminum heads. You will need certain headers to accommodate the P head for spark plug access and I had the header made for it and still could take plugs out with headers on. My opinion from firsthand experience the P head sucks along with every other factory small block ford head. Get aftermarket heads. I will go as far to say that I would buy a set of Proform Aluminum heads and run them before I would put a set of GT40P heads on that's how bad the P head is in my experience.

    The difference in my car going from the GT40P head to Trickflow aluminum heads is unexplainable

    Again this is just my opinion from my firsthand experience with these GT40P heads and I personally hate them. Just trying to save you some trouble.

    Cameron


    Sent from my iPhone using Tapatalk
     
  11. DavidBoren

    DavidBoren Active Member

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    Thank you all for sharing. Got some good and some bad, which is awesome, as I like to hear both sides of the story.

    From the looks of it, GT40 top end nets roughly 240rwhp, GT40 top end and a cam can get up to 270. I think that will be just fine for what I am looking for.

    Thank you all again for the replies.

    PS. Firefighter, let me know how your set-up treats you.
     
  12. Firefighter181

    Firefighter181 Active Member

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    Good thoughts and insight here indeed.

    I just pulled my car out of storage yesterday so I will be starting on my car this weekend. I shall keep ya posted!
     
  13. DavidBoren

    DavidBoren Active Member

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    Nice. I look forward to hearing about your swap.