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  1. #1

    Default Stock 93 GT headers into 78 V8 Zephyr

    Would you happen to know if a pair of stock 85-93 Mustang GT headers (5.0) will bolt-on without fuzz into a '78 Zephyr/Fairmont with a stock 302 engine?
    The idea is to improve the exhaust (in addition to brakes & suspension) of this '78 Zephyr daily driver with cheap (factory) parts sourced from 85-93 Mustangs. If the factory 5.0L shorty headers fit OK, I'll also use a factory H pipe (cats gutted) to build the exhaust system on the 78 Zephyr.
    Thanks!
    Raul
    Last edited by chivaceae; 06-05-2019 at 11:53 AM.

  2. #2
    FEP Power Member mcb82gt's Avatar
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    96 Mustang wasn't a 5.0. So I doubt those would fit. I would use the 5.0 stock headers and the H pipe. You will need the dual exhaust h pipe hanger that bolts to the tranny mount.
    Mike

    Now stang-less.

    88 Cougar 5.0

  3. #3

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    Mike,

    Thank you for the information! I had a typo (I wrote 1996 instead of 85-93) in the first sentence. I will certainly look also for the double hump tranny crossmember to do this. Like I said, I am planning on improving a little the performance of this '78 Zephyr daily driver only with stock Mustang 5.0 parts sourced from junkyards and craigslist. This is an "extreme cheap", DIY (i.e. do it myself) project, with no show/competition intentions, just to enjoy driving it. BTW, the car is unmolested with about 56K original miles, being one more reason to keep it going only with the addition of a few factory "performance" parts.
    Thanks again,
    Raul
    Last edited by chivaceae; 06-05-2019 at 11:56 AM.

  4. #4
    FEP Super Member erratic50's Avatar
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    The Ford factory headers on 86-93 Mustangs are basically JUNK. They last and last but they are as restrictive as the day is long. They are a good part of why the 5.0L cars fall flat on their face at 5300 RPM. The other problem being the intake and so on, but that's another story.

    I would not waste my time with 86-93 headers. A large number of cast manifolds from Ford flow better than the factory headers do. The reason is the pinch welds by the flage are incredibly restrictive.

    You can weld up the pipes on the outside then grind out the insides until you have a smooth transition into the pipes. I have a pair of factory headers around that had this done to them back in the 80's before there were aftermarket parts available. It is very time consuming and really not worth it.

    Instead I'd grab a cheap set of 1 5/8" exhaust port to 2 1/2" exhaust flange shorties and call it a win. They are all over the place on Ebay for less than $100.00.

    You should be able to get the stock 2.25" H to bolt up, but a better answer is an aftermarket pipe. Again there are pipes out there used for cheap.

    anyway - that's what I would do.

  5. #5

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    They will bolt up, and can be found cheap in a lot of places. The performance value depends on what you are after, on a stock 78 302 you may pick up a little gas mileage. Many Mustang parts will fit , some with a bit of adjusting and some with no fuss
    1978 Mercury Zephyr boxtop 5.0 EFI T5Z 8.8
    1999 Ford Contour 2.5 V6 5 speed
    2016 Ford Focus ST 2.0 Ecoboost 6 speed

  6. #6

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    Quote Originally Posted by erratic50 View Post
    A large number of cast manifolds from Ford flow better than the factory headers do.
    You should be able to get the stock 2.25" H to bolt up, but a better answer is an aftermarket pipe. Again there are pipes out there used for cheap.
    Thanks for your reply. What Ford factory cast exhaust manifolds do you think flow better than the shorty 86-93 headers? I do not mind doing some porting myself on a suitable set of cast manifolds if they flow better and upping a little on the HP (and perhaps the MPG) without sacrificing the low end-torque that supposedly is found on the stock '78 302 engine.

    My funds are tight, but I am fairly handy and have tools to work on this car. And using cheap factory parts (sourced in junkyards, craigslist and maybe even eBay) that improve on the daily-driving performance and handling of this car is what I am after (which will also contribute to keep its "originality"). For example, I aim to quasi-recreate the 93 Cobra suspension setup you have posted extensively about, and on the braking department emulate the package offered on 78-79 taxi/police Fairmonts (again, all to be done on the cheapest possible level, with me providing loving, careful, patient labor with attention to detail).
    Thanks again for your replies and all your postings that I have read on so far.
    Raul

    PS. I might be able to get me a free pair of E7 iron heads from a 96-97 Explorer, and if they can be a bolt-on fit on the flat tappet '78 302 engine (139 HP; 250 ft-lb) on this 78 Zephyr, I could certainly do some porting and refreshing on these heads if they can significantly improve on the stock engine performance (adding a the above mentioned factory (ported) exhaust manifolds or headers.
    Last edited by chivaceae; 06-05-2019 at 11:52 PM.

  7. #7

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    Quote Originally Posted by ukravit View Post
    They will bolt up, and can be found cheap in a lot of places. The performance value depends on what you are after, on a stock 78 302 you may pick up a little gas mileage. Many Mustang parts will fit , some with a bit of adjusting and some with no fuss
    Thank you for following my drift. I just want to enjoy driving the car, upgrading its (engine, braking and suspension) performance on the cheap, recycling factory parts from the sportier Fox Mustangs.
    In the 1995-1999 period I had two Fairmonts, a stock '78 2-dr sedan, and a '83 Futura to which I transplanted most of the drivetrain and suspension from a salt-rusted Mustang 85 GT (and in which I ended up blowing a lot more money than what is was worth).
    On this '78 Zephyr Z7 I want to do something similar, but on the cheapest possible way as far as parts buying, but being more patient and "crafty" with my DIY labor. I am definitively after a car with the best compromise of fuel economy (MPG) with a little hump from recycled factory parts. My daily driven, factory original 1979 F150 (4WD, SWB, 4-spd), while fun and great looking, is a gas guzzler (12-13 MPG).
    Thanks,
    Raul
    Last edited by chivaceae; 06-07-2019 at 12:23 PM.

  8. #8
    FEP Power Member mcb82gt's Avatar
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    Quote Originally Posted by chivaceae View Post
    Raul

    PS. I might be able to get me a free pair of E7 iron heads from a 96-97 Explorer, and if they can be a bolt-on fit on the flat tappet '78 302 engine (139 HP; 250 ft-lb) on this 78 Zephyr, I could certainly do some porting and refreshing on these heads if they can significantly improve on the stock engine performance (adding a the above mentioned factory (ported) exhaust manifolds or headers.

    96-early 97 Explorer heads are GT40 heads, have 4 bars cast into the front/rear of head. They flow better than the E7 heads.

    I'm unsure about PTV clearance with 78 302. I suspect the pistons are notched, but I don't know that for sure.
    Mike

    Now stang-less.

    88 Cougar 5.0

  9. #9
    FEP Super Member erratic50's Avatar
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    As far as which cast manifolds flow as well or better than 86-93 header - I wish I could tell you for sure. The last set I sourced was in the 90’s out of a pile of Ford manifolds that were going to get hauled to scrap.

    I do know cleaning up the headers inside each pipe at the pinch welds by the flange makes an enormous difference. Clean up inside then bolt it firmly to a head and weld the areas ground out from the outside to keep the structural integrity of the headers. Keep going until you have a nice smooth transition just like an aftermarket header has.

  10. #10

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    Quote Originally Posted by mcb82gt View Post
    96-early 97 Explorer heads are GT40 heads, have 4 bars cast into the front/rear of head. They flow better than the E7 heads.
    I'm unsure about PTV clearance with 78 302. I suspect the pistons are notched, but I don't know that for sure.
    If I get the Explorer GT40 heads I'll make sure to check first on the PTV (piston-to-valve) clearance on the '78 302 engine, as to not spend time/money on the GT40 heads. Otherwise I might work a bit on porting & rebuilding the stock '78 302 heads, maybe even shaving it a little to bump compression (I understand stock compression on 78-79 302s is around 8.1 to 8.4:1).

  11. #11
    FEP Power Member mcb82gt's Avatar
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    I had a typo, the GT40 heads have 3 bars, the GT40P heads have 4 bars. Sorry.
    Mike

    Now stang-less.

    88 Cougar 5.0

  12. #12

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    I think the trans crossmember is a little different in 81 and older cars
    Just get some used Mac headers world of difference
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