Close



Page 1 of 2 12 LastLast
Results 1 to 25 of 31
  1. #1
    FEP Member dlgourn's Avatar
    Join Date
    Oct 2009
    Location
    Grants Pass, OR
    Posts
    346

    Default Different between 84 and 85 Mustang 5.0 exhaust?

    Im looking complete factory exhaust system for 84 5.0 I only know 85 got dual exhaust system. Im wondering headers y pipe and big cat in middle are same between 84 and 85? Thanks.

  2. #2
    FEP Senior Member
    Join Date
    Jan 2011
    Location
    Vancouver BC Canada
    Posts
    784

    Default

    I believe that the 84 5.0 still had regular cast iron exhaust manifolds, where the 85 had the new "tube headers", that were unique to 85, as they were the only year with the tubes for the dual snorkle air cleaners hot air setup. The 85 does have dual tailpipes and mufflers, but only has a single pipe between the headers and main catalytic convertor. I can`t say if the parts are interchangable, although they do look similar.
    1978 Fairmont 2 door sedan, 428CJ 4speed. 9.972ET@132.54mph. 1.29 60 foot
    Replaced the FE big block with my 331/4 speed in my Fairmont, best 10.24ET @128 MPH.
    1985 Mustang LX hatchback NHRA Stock Eliminator 302 4 speed best in legal trim 12.31@107 mph, but has gone 11.42@115 with aftermarket intake, carb, and iron Windsor Jr. heads.New for 2012! 331 cube SB Ford, AFR 185 heads, solid flat tappet cam, pump gas; 10.296ET@128.71 mph, 1.37 60 foot.
    1979 Zephyr Z7, all original 302 auto, 2nd owner.

  3. #3

    Default

    All '85 4V engines got tube steel manifolds, Y-pipe, single cat, single mid-pipe, dual mufflers, dual tailpipes, stailess tips. I think there was a smaller cat (?) in the passenger side of the Y-pipe.

    Early (through 11/18/84) '85 CFI engines got '84 exhaust (cast iron manifolds, Y-pipe, single cat, single muffler, single tailpipe, twin stainless tip). After 11/18/84, CFI engine got same exhaust as '85 4V engine.
    Axle Tag Decoder
    Buck Tag Decoder
    Door Tag Decoder
    Owner Card Decoder
    Transmission Tag Decoder
    VIN Decoder

    FEP Registries: Black Magic & Crimson Cat / Cobra / Dominator / G.T.350 / LTD LX/Police & Marquis LTS / M81 / Pace Car / Predator / Saleen / Turbo GT & Turbo RS / Twister II

    Wanted (Dead or Alive): VINs, door tags, buck tags, build sheets, window stickers, owner cards, transmission tags, axle tags

  4. #4

    Default

    ^correct. Although any of the tube headers work fine. Mine does not have the heat risers and it starts and idles fine.
    are you asking if you can bolt the 85 mid-pipe back system to the 84 Y pipe? That is a good question. I am not sure on that. It won't be TRUE dual exhaust as noted above though. That would require the 86-93 H pipe. I put a complete 92 LX 5.0 exhaust system on my 84 and it fit fine. Just have to fix a hanger for the passenger side muffler and tailpipe. I think the holes for the muffler bracket are there and 1 out of holes for the tailpipe hanger are there. I had enough to get it to the muffler shop without tearing anything up.
    Liberty once lost is lost forever.

    John Adams
    July 7, 1775

  5. #5
    FEP Member
    Join Date
    Sep 2011
    Location
    Clarksville Indiana
    Posts
    118

    Default

    Quote Originally Posted by homer302 View Post
    ^correct. Although any of the tube headers work fine. Mine does not have the heat risers and it starts and idles fine.
    are you asking if you can bolt the 85 mid-pipe back system to the 84 Y pipe? That is a good question. I am not sure on that. It won't be TRUE dual exhaust as noted above though. That would require the 86-93 H pipe. I put a complete 92 LX 5.0 exhaust system on my 84 and it fit fine. Just have to fix a hanger for the passenger side muffler and tailpipe. I think the holes for the muffler bracket are there and 1 out of holes for the tailpipe hanger are there. I had enough to get it to the muffler shop without tearing anything up.
    you will also need a double hump crossmember if your putting duals all the way. your car has a single hump crossmember

  6. #6
    FEP Member dlgourn's Avatar
    Join Date
    Oct 2009
    Location
    Grants Pass, OR
    Posts
    346

    Default

    OK I need to explain more about my 84 Mustang. I bought it, they have factory cast iron exhaust manifold, custom made h pipe, two flowmaster mufflers, and custom made dual tail pipes. All done by muffler shop. I want to replace it to factory exhaust system. I will have to replace from dual mufflers and dual tailpipe to 84 single muffler and single tailpipe with twin stainless tips. I was wondering if 85 front y-pipe and single mid-pipe are same as 84?

  7. #7
    FEP Super Member onetrackrider's Avatar
    Join Date
    Apr 2009
    Location
    Denver, Colorado
    Posts
    4,660

    Default

    You could get on Rock Auto & cross reference part numbers between the two years..Also here's a visual reference of a stock 85 set-up..
    http://albuquerque.craigslist.org/pts/2727619399.html
    Last edited by onetrackrider; 12-31-2011 at 01:18 PM.
    Current rides:
    89 LX 5.0, 5 -spd..the Lemon
    86 RS Capri 5.0 Auto...
    86 LX Colorado SSP 5.0 5-spd (Sadly Sold)
    85.5 SVO, Finally Got Boost
    83 RS Capri 5.0, 5-spd (another sadly sold)

  8. #8
    FEP Power Member Saturn V's Avatar
    Join Date
    Jan 2011
    Location
    Houston, TX
    Posts
    1,289

    Default

    I'm recycling this old thread, because I didn't see a direct answer to the OP's question, and I've not received a solid reply to my similar questions. So let me try again.

    I've read that 84 and 85 carb y-pipe and main cat are the same, but then I've also read that the 85 parts are larger. On my 84-1/2 Mustang, the pipes from the stock exhaust manifolds measure about 2-1/8" O.D., the pipe going into the main cat is about 2-1/4" O.D., and the pipe at the main cat outlet is 2-1/2" O.D. I'm pretty sure that the y-pipe and main cat are original, but not sure about the pipe at the main cat outlet. Also, I've read that the flapper valve is larger for 85. The pic below is of the lightoff cat (on passenger side of the y) which shows the part number ... E3ZC-AA. I believe the correct, complete part number is E3ZC-5F250-AA and that the 5F250 (upper right in photo) is a generic part number for the y-pipe and is the same across different years and models.

    Can someone please confirm the y-pipe part number for 85, whether or not the 85 parts are larger, maybe take some measurements of the 85 parts, and provide photos of 84 and 85 flapper valves? I've got new JBA carb headers ready to install, but if the y-pipe, flapper, and main cat are larger for 85, I'll try to source those for the install. My plan is to keep the single exhaust.



    Present: '84.5 Mustang GT T-top, '06 Mazdaspeed6
    Past: '79 5.0 Capri, '86 Buick GN, '90 Mustang GT, '92 SHO, '95 SHO
    Browse cover pages of my Fox Chassis related library

  9. #9
    FEP Power Member bluesfannoz's Avatar
    Join Date
    Aug 2007
    Location
    Lawrence, Ks
    Posts
    2,204

    Default

    I don't have measurements, but those pieces look the exact same as what I just had put back in my 85. They were originally removed from a early year 85 model.
    Steve
    "Taillights in Your Face Jack? You've just been Dominated!"
    # Link to Facebook Dominator Mustang Fans # # Link to Facebook Predator Mustang Fans #
    # Link to Facebook Twister Mustang Fans #
    Current Stangs: Stangless
    Previously owned:
    84 Black GT, 85 Black T-Top Dominator GT # Link to Restoration Thread # 85 Dominator GT RIP 1995, 85 Predator GT, 83 Dominator GT, 82 Mustang GT

  10. #10

    Default

    I have the left overs from my 85 GT's exhaust laying in my yard (recycling pile). I will check them out tomorrow and see if the part #'s match yours.

  11. #11

    Default

    Since I'm a night owl and this post peaked my interest, I decided to grab the flash light and check my parts out.
    In 94, I parted a 5 speed 85 GT and a year or so later I bought another that I slowly modified into a race car. I saved the y pipes and cats from both of these cars ( along with the headers) knowing they were a 1 year thing. I don't have any info left about these cars so I can't tell the build date of either car. The first one I grabbed had the exact same part # on the y pipe and also the converter. I figured they are all the same as the one the OP has. The 2nd cat I have has a honey comb bolt on heat shield so I can't see the part #. I then grabbed the 2nd y pipe and its different. It has a E4 part # and it is quite obvious that the tubes are bigger just by looking at it. I will take some pics tomorrow.

  12. #12
    FEP Super Member Travis T's Avatar
    Join Date
    Jan 2011
    Location
    China Grove, North Carolina
    Posts
    5,267

    Default

    A sort of weird thing I noticed - I've had three 84 GTs total. Two were five speeds, one an AOD. The five speed cars had that small converter, the AOD car didn't. The exhaust appeared untouched on that car so there may be another difference when it comes to 84s themselves.
    1984 Mustang GT owned since 1991 (first car). Mercury Mountaineer GT-40P engine, some suspension mods, currently undergoing a five lug SN95 brake upgrade and more suspension mods. Some minor body and interior mods have been done as well.

    2004 GT convertible, 2001 Taurus LX, 1994 F150, 1950 F-1 Ford Pickup

  13. #13
    FEP Senior Member tbirdman's Avatar
    Join Date
    Dec 2006
    Location
    Middletown, DE
    Posts
    876

    Default

    Name:  85 Exhaust MT.jpg
Views: 3190
Size:  90.1 KB
    If they take my stapler, then I'll set the building on fire...

    85 Mustang GT

  14. #14
    FEP Power Member Saturn V's Avatar
    Join Date
    Jan 2011
    Location
    Houston, TX
    Posts
    1,289

    Default

    Quote Originally Posted by bluesfannoz View Post
    I don't have measurements, but those pieces look the exact same as what I just had put back in my 85. They were originally removed from a early year 85 model.
    Yes, I've always thought that pics of 85 exhaust look the same as my 84 exhaust, but I still have doubts based on what others have said.

    Quote Originally Posted by boboli View Post
    Since I'm a night owl and this post peaked my interest, I decided to grab the flash light and check my parts out.
    In 94, I parted a 5 speed 85 GT and a year or so later I bought another that I slowly modified into a race car. I saved the y pipes and cats from both of these cars ( along with the headers) knowing they were a 1 year thing. I don't have any info left about these cars so I can't tell the build date of either car. The first one I grabbed had the exact same part # on the y pipe and also the converter. I figured they are all the same as the one the OP has. The 2nd cat I have has a honey comb bolt on heat shield so I can't see the part #. I then grabbed the 2nd y pipe and its different. It has a E4 part # and it is quite obvious that the tubes are bigger just by looking at it. I will take some pics tomorrow.
    Thanks, we'd really like to see some pics with part numbers!

    Quote Originally Posted by Travis T View Post
    A sort of weird thing I noticed - I've had three 84 GTs total. Two were five speeds, one an AOD. The five speed cars had that small converter, the AOD car didn't. The exhaust appeared untouched on that car so there may be another difference when it comes to 84s themselves.
    I believe only the carb'd cars got the small lightoff cat on the passenger side, to help reduce emissions during rich startup on the choke? Perhaps the AOD CFI system more precisely managed fuel enrichment on cold start, obviating the need for the lightoff cat?


    tbirdman, thanks for that part number diagram ... what is the source document? I'd like to get one of those. It's interesting that the y-pipe is an E4 number, but the main cat is E3, which is probably what is on my 84 (would need to remove the heat shield to look for the part number).
    Present: '84.5 Mustang GT T-top, '06 Mazdaspeed6
    Past: '79 5.0 Capri, '86 Buick GN, '90 Mustang GT, '92 SHO, '95 SHO
    Browse cover pages of my Fox Chassis related library

  15. #15

    Default

    Here's some pics

    You can kind of see how the tubing on the E3 is a smaller diameter and more crimped than the E4

    A closer shot of the part #'s.
    E3ZC-AA VS E4ZC


    Here is the best I could do at the time to compare pipe diameters. In case the pictures disappear the E3 has a outer pipe diameter of 1.77 inches were it enters the small cat on the passenger side. The E4 has a diameter of 2.29 inches at the same location.


    Here is a pic looking down on the 2 y pipes passenger side connectors. It may be hard to see but the E4 (right) is larger than the E3(left)


    The outlets were the same, which makes sense since they seem to all use the same cat.
    Anything else I can take pics of let me know

  16. #16
    FEP Power Member Saturn V's Avatar
    Join Date
    Jan 2011
    Location
    Houston, TX
    Posts
    1,289

    Default

    boboli, you are the man!!! Thank you so much for taking the time to document these differences. I've not seen this information anywhere else. I didn't get a good measurement on my passenger side pipe that goes into the small cat (measured about 2" on the driver's side), but I bet it's about the same as the 1.77" that you measured ... it does look a little smaller and more crimped than the driver's side.

    I tend to think you are right ... 83-85 main catalytic converters are all the same, unless someone else can show a difference?
    Present: '84.5 Mustang GT T-top, '06 Mazdaspeed6
    Past: '79 5.0 Capri, '86 Buick GN, '90 Mustang GT, '92 SHO, '95 SHO
    Browse cover pages of my Fox Chassis related library

  17. #17

    Default

    Since you asked about the heat riser, I found one of the 85 ones I have. I think I tossed the other long ago. There are 2 on ebay right now( 1 used and 1 new) that look exactly the same.
    from the rear


    from the engine side


    the label on the vacuum canister has long since been destroyed, so I can't read any #'s. The label almost looks to have a bluish color, but I can't say if that is original or just from time. The original on ebay has a red sticker. Maybe they are color coded to size? The only cast # on the valve body is a #4 right at the corner, near the vacuum canister.

  18. #18
    FEP Power Member Saturn V's Avatar
    Join Date
    Jan 2011
    Location
    Houston, TX
    Posts
    1,289

    Default

    boboli, thanks again for the excellent pics and measurements of the flapper valve. I'll have to measure the one on my 84 when I take it off, but if your 85 flapper is 2.3" at the outlet, I'm pretty sure that's larger than the one in my 84, because the O.D. of the driver's side pipe on my car is only about 2.1"
    Present: '84.5 Mustang GT T-top, '06 Mazdaspeed6
    Past: '79 5.0 Capri, '86 Buick GN, '90 Mustang GT, '92 SHO, '95 SHO
    Browse cover pages of my Fox Chassis related library

  19. #19
    FEP Senior Member burntorange84's Avatar
    Join Date
    Dec 2006
    Location
    GT (georgetown), TX
    Posts
    740

    Default

    Quote Originally Posted by dlgourn View Post
    OK I need to explain more about my 84 Mustang. I bought it, they have factory cast iron exhaust manifold, custom made h pipe, two flowmaster mufflers, and custom made dual tail pipes. All done by muffler shop. I want to replace it to factory exhaust system. I will have to replace from dual mufflers and dual tailpipe to 84 single muffler and single tailpipe with twin stainless tips. I was wondering if 85 front y-pipe and single mid-pipe are same as 84?
    Is this system on your 84 predator?

    O2Z06 could probably give you more info; but what you describe sounds like the Predator mods to the exhaust that I've seen.

    In short as you've seen, the 84 system is smaller sized overall than the 85 system.

    -j
    _________________________________________
    1984.5 Mustang GT: org. 5.0, 5spd, 3.27's;
    GT-40's w/93 exhaust; t-bird TC brakes....

  20. #20

    Default

    I would like to update the info I posted above.
    I think my assertion that both my y pipes came off of 85 GT's is incorrect. When I posted it, I could only remember taking the exhaust off of two 85 gt's, but I recently remembered I did own an 84 GT convertible for a few months ( probably 8 years ago). It had a bad motor or transmission. I took it apart, gave up on fixing it,and then sold just the body off. I think the E3 y pipe was from the 84 GT. So the E4 would be correct for late 84's(?) and 85 GT's. The E3 should be correct for 83 and early 84's

  21. #21
    FEP Power Member Saturn V's Avatar
    Join Date
    Jan 2011
    Location
    Houston, TX
    Posts
    1,289

    Default

    Quote Originally Posted by boboli View Post
    I would like to update the info I posted above.
    I think my assertion that both my y pipes came off of 85 GT's is incorrect. When I posted it, I could only remember taking the exhaust off of two 85 gt's, but I recently remembered I did own an 84 GT convertible for a few months ( probably 8 years ago). It had a bad motor or transmission. I took it apart, gave up on fixing it,and then sold just the body off. I think the E3 y pipe was from the 84 GT. So the E4 would be correct for late 84's(?) and 85 GT's. The E3 should be correct for 83 and early 84's
    Thanks for the clarification ... I wondered how an E3 pipe showed up on an 85. I can't say for sure, but I tend to doubt that even late 84s came with the E4 pipe. My 84 was built in July 84 and has the E3 pipe. But this does remind me of the anecdotal stories about some late 84s with ~200HP that had some of the 85 improvements ....
    Present: '84.5 Mustang GT T-top, '06 Mazdaspeed6
    Past: '79 5.0 Capri, '86 Buick GN, '90 Mustang GT, '92 SHO, '95 SHO
    Browse cover pages of my Fox Chassis related library

  22. #22
    FEP Power Member fgross2006's Avatar
    Join Date
    Sep 2014
    Location
    Freeport NY
    Posts
    2,024

    Default

    Quote Originally Posted by boboli View Post
    Since you asked about the heat riser, I found one of the 85 ones I have. I think I tossed the other long ago. There are 2 on ebay right now( 1 used and 1 new) that look exactly the same.
    from the rear


    from the engine side


    the label on the vacuum canister has long since been destroyed, so I can't read any #'s. The label almost looks to have a bluish color, but I can't say if that is original or just from time. The original on ebay has a red sticker. Maybe they are color coded to size? The only cast # on the valve body is a #4 right at the corner, near the vacuum canister.
    I'd like to get some info on this set up as well.

    later this summer I hope to convert to a dual exhaust. Currently I have a Y pipe and single exhaust. I am sure I have a flapper valve as I have seen it when my car is on the lift. I do not know if the one pictured is the one that goes in an 84 5.0 CFI.

    I simply want to find a replacement just to get the old part out and upgrade when I'm replacing the exhaust system. I have seen a few online that look like the one pictured, however I don't think mine is vacuum actuated. I'll need to get it on a lift again to be sure. but I cant see it at all from the engine compartment and Im sure I don't have any vacuum line going down there.

    If I do have vacuum feed, wheres it coming from? cant be the vacuum solenoid cluster on the driver fender. They all control EGR, TAD/TAB and VOTM

    Id like to find the correct part and part number for an 84

    thanks

  23. #23

    Default

    If you're going OEM style duals, then you don't need a flapper valve. It was only used on single (or single-cat, Y'ed back to dual) exhausts.
    '88 Mustang GT convertible, T5, 3.08:1 gears. 5.0 Explobra Jet: A9L Mass Air conversion, Fenderwell Mac cold air intake, 70mm MAF meter = 4.6 T-Bird/Cougar housing + '95 Mustang F2VF-12B579-A1A sensor, aftermarket 70mm throttle body and spacer, Explorer intakes, GT40P heads with Alex's Parts springs and drilled for thermactor, Crane F3ZE-6529-AB 1.7 "Cobra" roller rockers, Ford Racing P50 headers, Mac H-pipe, Magnaflow catback, Walbro 190 LPH fuel pump, UPR firewall adjuster and quadrant with Ford OEM cable, 3G conversion ('95 Mustang V6), Taurus fan, rolled on Rustoleum gloss white paint...
    Past Four Eyes: Red well optioned '82 GT 5.0, Black T-top '81 Capri Black Magic 3.3L 4 speed, Black T-top '84 Capri RS 5.0 5 speed.Over 200,000 miles driven in Four Eyes, and over 350,000 in Fox Body cars.

  24. #24

    Default

    The flapper valve was used on carbureted and CFI 5.0 engines, to aid cold driveability, by warming the
    floor of the intake manifold. It was not used on the SEFI cars, because, being port-injected, they are
    not a wet-flow system. If you want to keep this feature, you will need the '85 flapper valve. Also if you
    want to use the '85-only shorties with the hot air tubes to the air cleaner, you will need the '85 flapper
    valve, or modify a later set of shorties to accept the heat tubes.

    When I converted my '85 hatch to full duals, I welded a short piece of 2" exhaust tubing to the driver-
    side '86-up JBA shorty, to connect to the air cleaner. (Passenger-side JBA shorty is the '85 version,
    which already had such a tube on it.) I am not using the flapper valve, since it rarely gets cold enough
    here to really matter. And even in Kalifornia, it has never been questioned.

    If you use the '85-spec headers and flapper, the driver side headpipe will need about 1" sectioned out
    of it, to compensate for the thickness of the flapper valve.

    If you're keeping the cats, you will need the '86+ catalyst air tube. This will bolt on in place of the one
    you have now, using the same air hose connections.

    You will need a double-hump crossmember, and the AOD-specific version of the exhaust hanger mount.

    You will need the passenger-side muffler and tailpipe hanger hardware.

    You will need to convert to a single in-tank fuel pump, to make room for the passenger-side muffler.

    You will also need to convert the rear brake lines to use the center-mount rear brake hose, to make
    room for the passenger-side tailpipe.
    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

  25. #25
    FEP Power Member fgross2006's Avatar
    Join Date
    Sep 2014
    Location
    Freeport NY
    Posts
    2,024

    Default

    Quote Originally Posted by JACook View Post
    The flapper valve was used on carbureted and CFI 5.0 engines, to aid cold driveability, by warming the
    floor of the intake manifold. It was not used on the SEFI cars, because, being port-injected, they are
    not a wet-flow system. If you want to keep this feature, you will need the '85 flapper valve. Also if you
    want to use the '85-only shorties with the hot air tubes to the air cleaner, you will need the '85 flapper
    valve, or modify a later set of shorties to accept the heat tubes.

    When I converted my '85 hatch to full duals, I welded a short piece of 2" exhaust tubing to the driver-
    side '86-up JBA shorty, to connect to the air cleaner. (Passenger-side JBA shorty is the '85 version,
    which already had such a tube on it.) I am not using the flapper valve, since it rarely gets cold enough
    here to really matter. And even in Kalifornia, it has never been questioned.

    If you use the '85-spec headers and flapper, the driver side headpipe will need about 1" sectioned out
    of it, to compensate for the thickness of the flapper valve.

    If you're keeping the cats, you will need the '86+ catalyst air tube. This will bolt on in place of the one
    you have now, using the same air hose connections.

    You will need a double-hump crossmember, and the AOD-specific version of the exhaust hanger mount.

    You will need the passenger-side muffler and tailpipe hanger hardware.

    You will need to convert to a single in-tank fuel pump, to make room for the passenger-side muffler.

    You will also need to convert the rear brake lines to use the center-mount rear brake hose, to make
    room for the passenger-side tailpipe.

    all I can say is wow. I wonder if its even worth the trouble.

Page 1 of 2 12 LastLast

Posting Permissions

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