Close



Results 1 to 5 of 5
  1. #1
    FEP Power Member Broncojunkie's Avatar
    Join Date
    Jan 2015
    Location
    Barboursville, WV
    Posts
    1,773

    Default 79 Cobra 5.0 c4?

    Anything special about a C4 in a 79? Is there any reason I can't use it behind a solid 300hp motor? I'm taking it to a local guy so he can go through it and maybe do some performance mods. I don't know much about the autos. Haven't used or owned a c4 in 20 yrs.

  2. #2
    FEP Power Member slow84lx's Avatar
    Join Date
    Apr 2006
    Location
    Dallas, TX
    Posts
    1,562

    Default

    The C4 can be built to hold lots of power for fairly low cost but it will keep your engine revving on the highway. If decent gas mileage is important an overdrive transmission will be a better choice.

  3. #3

    Default

    The only thing 'special' about the C4 in a '79, is common to all C4s in Fox applications. The Fox C4s use a
    large bellhousing and 164-tooth flexplate, and 11.5" bolt circle, same as the "pan fill" C4s, even though
    they are still a "case fill" transmission. If you don't take this into account when you're ordering parts, you
    will likely get the wrong torque converter. Most performance converter manufacturers assume a case-fill
    C4 will always have the smaller 157 tooth flexplate. Performance Automatic PA26216 is a nice street-strip
    converter that fits the Fox C4.

    A V8 C4 will handle 300 HP just fine, but do use a good cooler, particularly if you have a higher-stall converter.
    If you're rebuilding one for street-strip use, there are upgraded clutch materials available, as well as ways to
    add an additional disc to the forward clutch without resorting to thinner steels. Unless you're planning to be
    doing dragstrip launches on slicks, the C4 doesn't need much else.

    The hands-down best shift kit for a C4 is the Trans-Go Performance 40-2.
    Cheers,
    Jeff Cook

    '85 GT Hatch, 5-speed T-Top, Eibachs, Konis, & ARE 5-Spokes ... '85 GT Vert, CFI/AOD, all factory...
    '79 Fairmont StaWag, 5.0, 62K original miles ... '04 Azure Blue 40th Anny Mach 1, 37K original miles...
    2012 F150 S-Crew 4x4 5.0 "Blue Coyote"... 65 coupe, 289 auto, Pony interior ... '67 coupe 6-cyl 4-speed ...
    '68 Vert, Mexican block 307 4-speed... '71 Datsun 510 ...
    And a 1-of-328 Deep Blue Pearl 2003 Marauder 4.6 DOHC, J-Mod, 4.10s and Lidio tune

  4. #4
    FEP Power Member Broncojunkie's Avatar
    Join Date
    Jan 2015
    Location
    Barboursville, WV
    Posts
    1,773

    Default

    Great info, guys! Thanks!

    I realize the c4 isn't best for highway use, but I think the problem most folks have with it is that they are running a low gear. I plan on keeping a highway gear and making it a little more fun to drive by swapping in a 351w or built roller 302. It will mainly see the occasional local cruise-in or Mustang club cruise.

    My main concern was that there was something about the oem transmission that makes it weaker than previous c4's. I mean, just look at the difference between...say...the old toploaders vs the srod.

    I was planning to have the extra c4 that's been lying around rebuilt and then swap that into the 79. After reading through your info, it looks like I'd probably be better off just pulling this one out and taking it to him. No big deal. The motor has to come out anyway, so I can repaint the engine bay.

  5. #5

    Default

    I personally like 3.27 gears behind a C4. Nice balance between acceleration and decent cruising RPM,
    especially when you don't have overdrive.
    Cheers,
    Jeff Cook

    '85 GT Hatch, 5-speed T-Top, Eibachs, Konis, & ARE 5-Spokes ... '85 GT Vert, CFI/AOD, all factory...
    '79 Fairmont StaWag, 5.0, 62K original miles ... '04 Azure Blue 40th Anny Mach 1, 37K original miles...
    2012 F150 S-Crew 4x4 5.0 "Blue Coyote"... 65 coupe, 289 auto, Pony interior ... '67 coupe 6-cyl 4-speed ...
    '68 Vert, Mexican block 307 4-speed... '71 Datsun 510 ...
    And a 1-of-328 Deep Blue Pearl 2003 Marauder 4.6 DOHC, J-Mod, 4.10s and Lidio tune

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •