gasket matching / gt40x heads

Discussion in 'Fox 5.0 Mustang Tech' started by 5.0TailPipeHump, Jan 8, 2009.

  1. Well im wanting to know if there is any advantage to gasket matching, i have a cobra lower that has a smaller port going to my heads which has a slightly bigger port, would it be worth it to match em up?

    1 more question , im looking into a set of gt40x heads for 650 assembled, would this be worth it to give em a try , im kinda on a bit of a budget right now and i think this would be a pretty good upgrade from the e7s i have on there right now , am i right. If i do go ahead im thinking of having a cam in there while the heads are getting installed, just not sure on what cam to run with the gt40x 303.

    # Chamber Size: 64cc
    # Intake Volume: 178cc
    # Intake Valve Dia.: 1.94''
    # Intake Flow: 240 cfm @ .550'' Lift
    # Exhaust Volume: 62cc
    # Exhaust Valve Dia.: 1.54''
    # Exhaust Flow: 170 cfm @ .550'' lift
  2. Gasket matching... minimal at best. Full pro port job..... Worth every penny.

    Gt40x are ok esp for that price if everything is in good shape. I think they are an old kind of outdated head design but should work for a budget build.
  3. Right on , how bout ppl running the Ecam , from what iv herd it give some nice torque down low , ill be shooting for the stars on this 1 come spring , just gotta get my mods together 1st and am hoping for aleast 300hp.
  4. Well i got me some ford racing heads from a guy who knew nothing about them and had them on his car for a short while ,he said they were X303 but it is stamped X302 assembled with 1.7 rockers on these heads? , are they 1.7 , is there away i can check, iv never took apart a head .

    f3zm-6049 is on the aluminum head and tryed to serch this # but came up with nothing . Wonder if ford changed they part # on em.

    With this set up what would be an ideal cam to go with .

    Any help would be fantastic .



    Attached Files:

  5. here is what I found
    M-6049-X302* Bare Head (64cc Chamber)
    M-6049-X303* Complete Head (64cc Chamber)
    M-6049-X304* Bare Head (58cc Chamber)
    M-6049-X305* Complete Head (58cc Chamber)

    For use on 289/302/351 Windsor-style engines

    Improved air flow over original GT-40 aluminum heads

    Intake flows approximately 240 cfm at .550" lift (at 28" of H20)

    Exhaust flows approximately 170 cfm at .500" lift (at 28" of H20)

    Machined for 1.94" Intake and 1.54" exhaust valve diameters

    Unlike some aftermarket heads our GT-40 heads use either GT-40 or aftermarket performance: intake manifolds, headers, and valve covers.

    Intake port volume 178cc, exhaust port volume 62cc

    High temperature exhaust valve seats. Thick deck for improved sealing, increased section thickness in critical areas for porting, and webbed rocker bosses for improved strength. Designed for bolt-on rocker arms, machined for tapered seat spark plug or gasketed. Compatible with Ford Racing intakes, headers, and valve train components. Can be machined for diagonal exhaust header flange mounting.

    High quality original equipment style 356-T6 aluminum castings, machining and components

    Each aluminum head weighs approximately 22 lbs. – approximately 25 lbs. lighter than each cast iron GT-40 head.

    These GT-40 style heads use AGSF-32C spark plugs

    Each GT-40X head is leak tested prior to assembly

    Head assembly consists of bare head M-6049-X302/X304 and GT-40 valve train kit M-6090-X302 featuring stainless steel valves. The valve springs are compatible with all Ford Racing roller camshafts.


    Will not fit 1986 5.0L with flat-top pistons unless pistons are notched for valve relief

    Must use head bolt kit M-6065-D289 to install cylinder heads on 289/302 blocks or head bolt and head gasket kit M-6051-A50 and intake gasket M-9439-A50/A51

    Check rocker arm clearance to valve springs with production rocker arms

    Check your intake manifold for port match, not all intakes are compatible due to the tall high-flow ports

    Must use M-9439-A50 intake gasket
  6. Thats what i thought , i just checked the numbers on the rockers and i belive that they are 1.7 Crane Cobra Roller Rocker Arms - 79-95.
  7. I'm running a very similar set-up to what you're looking at. Click the "my mod list" link in my signature for details. The dyno sheet below shows the difference between an unported Cobra manifold and a Tmoss-ported GT40 tubular intake on my car.


    Attached Files:

  8. Thanks for that withors , thats quite a difference in the torque range form a port job. Im definetely going with an ecam but am unsure if ill have the dredded clearence . Im sure i will cause i see alot of others going with this combo but with 1.7rr , i guess its always good to check that anyways.
  9. scrap the 1.7's. Get a nice set of 1.6's and you should be ok. U def want to check ptv clearance anyway.