GT40's on an 86 302

Discussion in 'Technical' started by JHodges, Jun 18, 2008.

  1. JHodges

    JHodges thumper

    Joined:
    Oct 14, 2006
    Messages:
    1,902
    Likes Received:
    5
    Trophy Points:
    132
    Location:
    Dora Alabama
    Vehicle:
    1972 Maverick 351w swap, 1965 Mustang 355 glide, 1993 civic daily driver
    I have an 86 302 out of a T-bird or a lincoln. It has a roller cam. I can buy rebuilt GT40 heads for $400. I was told it would not work because the 86 pistons had no valve reliefs. Would it work.
     
    JHodges, Jun 18, 2008
    #1
  2. markso125

    markso125 Member

    Joined:
    Aug 19, 2007
    Messages:
    1,714
    Likes Received:
    6
    Trophy Points:
    117
    Location:
    Lewiston Ut
    Vehicle:
    1972 maverick 2 door LDO
    Yes they will you need to watch the duration of the cam and ratio of the rocker arms to ensure that the pistons will not contact the valves.
     
    markso125, Jun 18, 2008
    #2
  3. EFIMAV

    EFIMAV Member

    Joined:
    Mar 9, 2002
    Messages:
    719
    Likes Received:
    7
    Trophy Points:
    90
    Location:
    Davenport Iowa
    Vehicle:
    1974 Maverick, FRPP 5.0, AOD, 3.80 equaloc
    I know several people that have run B-cams with this combo. Be sure you have good valve spings (not stock), maybe run a thicker head gasket as well
     
    Last edited: Jun 18, 2008
    EFIMAV, Jun 18, 2008
    #3
  4. scooper77515

    scooper77515 No current projects.

    Joined:
    Jun 30, 2004
    Messages:
    14,672
    Likes Received:
    73
    Trophy Points:
    233
    Location:
    Issaquah/Grand Coulee, WA
    Vehicle:
    Fresh out of Mavericks
    I have a similar setup, but with valve reliefs, and there is LOTS of extra room on mine, and I have a pretty big cam in there. I would guess that it would be safe to not have the reliefs.

    It is really easy to test it before you run it. Get a degreeing kit or buy a very light valve spring and put it on the valves, and slowly rotate the engine by hand and test how much clearance you have when the piston is up.
     
    scooper77515, Jun 19, 2008
    #4
  5. newtoford

    newtoford Member

    Joined:
    Mar 16, 2006
    Messages:
    5,475
    Likes Received:
    8
    Trophy Points:
    157
    Location:
    New Castle Delaware
    Vehicle:
    '76 Maverick, '76 Comet, 78 Monte Carlo, '85 Cutlass Supreme, '86 Regal Limited, '87 Grand Prix
    i thought it was only the grand marques that had the flat pistons?
     
    newtoford, Jun 19, 2008
    #5
  6. EFIMAV

    EFIMAV Member

    Joined:
    Mar 9, 2002
    Messages:
    719
    Likes Received:
    7
    Trophy Points:
    90
    Location:
    Davenport Iowa
    Vehicle:
    1974 Maverick, FRPP 5.0, AOD, 3.80 equaloc
    i thought it was only the grand marques that had the flat pistons?

    86 mustangs also, this was a unique year for the first year EFI mustang, intakes, heads and TBs (among other things) were year specific, 87 saw several changes for the mustang not sure about the crown vic etc.
     
    EFIMAV, Jun 19, 2008
    #6
  7. tim keck

    tim keck truckdrivintrailertrash

    Joined:
    Jul 4, 2004
    Messages:
    1,991
    Likes Received:
    7
    Trophy Points:
    111
    Location:
    sharps chapel,Tn
    Vehicle:
    '72 Comet, '75 Maverick, '85 F150 4x4 ,'93 F150,'75 F100,'77 Jeep Wagoneer,'91 Dodge D250 Cummins,'90 F150 xtra cab 4x4, '93 F150 4x4
    My Comet has an '86 shortblock(mustang)w/E7 heads and a B303 cam,got about 10,000 miles on it w/no problems.
     
    tim keck, Jun 19, 2008
    #7
  8. baddad457

    baddad457 Member

    Joined:
    Feb 24, 2007
    Messages:
    5,861
    Likes Received:
    141
    Trophy Points:
    171
    Location:
    Opelousas La.
    The 5.0's with E6SE heads got the no valve relief pistons, this included the 85 Stang, T-Birds, Cougars, Lincoln Town Car, Marquis and Crown vics. The big cars had these heads & pistons till the end of the 5.0's in em in 1991. There were a few pickups with em too.
     
    baddad457, Jun 20, 2008
    #8
  9. bmcdaniel

    bmcdaniel Senile Member Supporting Member

    Joined:
    Jul 2, 2002
    Messages:
    6,831
    Likes Received:
    685
    Trophy Points:
    318
    Location:
    York. PA
    Vehicle:
    '70 Maverick Grabber
    You always need to check piston-to-valve clearance when making a change like this. No one can tell you if your parts are gonna clear. Heads may have been milled, block decked, etc. You have to measure. DO NOT gain clearance by using a thicker head gasket. You want to keep the squish/quench clearance between the piston and head deck between .035" - .050" or the engine could be detonation prone.
     
    bmcdaniel, Jun 21, 2008
    #9
  10. MFG Racing Team

    MFG Racing Team Member

    Joined:
    Jun 23, 2008
    Messages:
    40
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    São Paulo, SP Brazil
    Vehicle:
    A whole bunch of Mavs in differente set-ups, from road race cars, to restomod and absolutelly original vehycles.
    Always...ALWAYS check PTV clearance. If you need help on that, let me know and I'll send you a step by step procedure.
    Ham
     
    MFG Racing Team, Jun 23, 2008
    #10

Share This Page