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Discussion Starter #1
What would be the best ignition system (coil , dist. wires, plugs) for Mustang 5.0 (1990) with the following mods:

•Engine:
302 CID BOSS BLOCK with GT-40 HEADS AND B CAM (Part M-6007-X302B)

FRPP Cobra 93 intake
Accufab 70MM Throttle Body
FRPP 24 LB/HR injectors
BBK 190 LPH fuel pump

BBK adjust fuel pressure regulator ( tuned from dyno for optimized AFR on 40 psi).
PRO-M 75mm Mass Air Meter

BBK Cold Air Fender Well intake

•Exhaust:

HEDMAN equal length headers
2 ½ MAGNAFLOW X-Pipes
MAGNAFLOW Cat-Back


•Cooling System:

Flex-A-Lite Black Magic Extreme 15" Electric Fan “Puller” – this fan is set on key on, it operates continuously
2 Perma-Cool Standard Electric Fans “Pusher” – operate with AC on.


•Drivetrain:

3.73 Ring and Pinion Gears “Ford Racing”
Eaton differential
King Cobra 10.5'' Clutch, Ford Racing Flywheel


•ACCs:
March Underdrive pulley set

Powermaster130 Amp Alternator
Optima battery (RED)
Air pump is deleted and many emission systems were deleted (No EGR )
 

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Fresh stock parts will suffice.
 

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Factory ign is plenty unless you are boosting. A good coil is always a plus!
 

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Discussion Starter #6
OK seems like everyone agrees that stock ign would be enough, what about Spark plugs??
 
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OK seems like everyone agrees that stock ign would be enough, what about Spark plugs??
GT40 Heads:
AUTOLITE

stock--765 (Heat Range - 5) [14mm, .708 Reach, 5/8" Hex]
1 step colder--764 (4) or 104 (4) [14mm, .708 Reach, 5/8" Hex]**
2 step colder--103 (3) [14mm, .708 Reach, 5/8" Hex]**
-----AR473 (3) [*recessed tip, racing plug]
-----AR472 (2) [*recessed tip, racing plug]

**The difference between the 764 plug and the 104/103 plug is the thread. The 764 plug is a half thread whereas the 104/103 plug is a full thread. The full thread plugs are duplicates of the half thread plugs in every other aspect, they both protrude the same amount into the combustion chamber.
 

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Discussion Starter #8
GT40 Heads:
AUTOLITE
stock--765 (Heat Range - 5) [14mm, .708 Reach, 5/8" Hex]
1 step colder--764 (4) or 104 (4) [14mm, .708 Reach, 5/8" Hex]**
2 step colder--103 (3) [14mm, .708 Reach, 5/8" Hex]**
-----AR473 (3) [*recessed tip, racing plug]
-----AR472 (2) [*recessed tip, racing plug]

**The difference between the 764 plug and the 104/103 plug is the thread. The 764 plug is a half thread whereas the 104/103 plug is a full thread. The full thread plugs are duplicates of the half thread plugs in every other aspect, they both protrude the same amount into the combustion chamber.
Thanks for the valuable information.. I am not sure if you meant part# by 765, 764....... I tried to look up from summitracing but no luck... do you have the exact part#s or the link???

Thanks again
 

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Discussion Starter #9
GT40 Heads:
AUTOLITE
stock--765 (Heat Range - 5) [14mm, .708 Reach, 5/8" Hex]
1 step colder--764 (4) or 104 (4) [14mm, .708 Reach, 5/8" Hex]**
2 step colder--103 (3) [14mm, .708 Reach, 5/8" Hex]**
-----AR473 (3) [*recessed tip, racing plug]
-----AR472 (2) [*recessed tip, racing plug]

**The difference between the 764 plug and the 104/103 plug is the thread. The 764 plug is a half thread whereas the 104/103 plug is a full thread. The full thread plugs are duplicates of the half thread plugs in every other aspect, they both protrude the same amount into the combustion chamber.
..... What do you recommend for my application?? stock is enough or shall I go for colder plugs?
 

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Colder plugs are for mainly power adders if you dont have any then run stock plugs. If you do have something then 1 step usually does it and helicoil 9mm plug wires too.
 

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Discussion Starter #11
Colder plugs are for mainly power adders if you dont have any then run stock plugs. If you do have something then 1 step usually does it and helicoil 9mm plug wires too.
Platinum is good ? any part number or link?
Thanks
 

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standard copper core plugs run the best..forget the platinum nonsense

and again,im going to disagree with reggie's info..764/104 was the stock heat range for the 1993-1995 cobra and gt40 explorer motors,not 765...

and if you look up aluminum gt40 heads recommended spark plug,ford lists motorcraft AGSF-32C,which cross references to an autolite 104 or 764
http://www.autolitecatalog.com/Competitor.aspx?b=A&pn=AGSF-32C&em=True

just go to your local auto store and say i want 8 autolite 764's..and then pay them and be on your way
 

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You want just plain ole copper plugs and why would you want such expensive plugs. It is a good habit also to pull and learn how to read them and since they are so cheap to change them every season.
 

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Discussion Starter #14
Thanks ... will check out that.
 

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Discussion Starter #15
standard copper core plugs run the best..forget the platinum nonsense

and again,im going to disagree with reggie's info..764/104 was the stock heat range for the 1993-1995 cobra and gt40 explorer motors,not 765...

and if you look up aluminum gt40 heads recommended spark plug,ford lists motorcraft AGSF-32C,which cross references to an autolite 104 or 764
Autolite - Competitor Cross Reference

just go to your local auto store and say i want 8 autolite 764's..and then pay them and be on your way
I was looking up in Motorcraft and found out that AWSF-42C is for1979-1995 5.0L with GT-40 cylinder heads (.054 gap) . This also cross references to 765 !! https://www.mustangsunlimited.com/itemdy00.asp?T1=AWSF42C 01 01

Any idea what is the difference before I buy?



 

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I was looking up in Motorcraft and found out that AWSF-42C is for1979-1995 5.0L with GT-40 cylinder heads (.054 gap) . This also cross references to 765 !! https://www.mustangsunlimited.com/itemdy00.asp?T1=AWSF42C 01 01

Any idea what is the difference before I buy?



Marunos,
I am the tech manager at Autolite and also own a 67 Mustang with a 430CI stroker windsor. I recommend using the XP103 spark plug with your heads and mods. This is just slightly colder than the stock heat range. It is a Iridium alloy fine wire spark plug with a nickel plated shell. It does cost 6.99 each at any autozone, advance or oreillys store. Why spend the money. These plugs take less voltage to fire,(giving your coil more dwell time) make a bigger flame kernal and do indeed make more power than a conventional plug. They are more resistant to pre-ignition as well. I used to run our racing plugs in my car (they are around 3 bucks each) and noticed a nice improvement in driveabilty with the XP's. You should go to our website, autolite.com and watch the autolite challenge video's, especially the first one on spark plug metallurgy and the 5th one on spark plug heat range. There is also a video on youtube about reading a plug, just search for autolite and don ward.:D
Good luck with your stang
 

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thats the first and only website i've ever seen recommend a 765 plug for gt40 heads

read it from the horses mouth..if anyone should know what the stock heat range is,it should be 1993 cobra owners

1993cobra.com said:
The ORIGINAL Cobra Motorcraft spark plug is AWSF-32C, stock number 434. Ford has replaced this plug with the AGSF-32C which carries a 4122 stock number. The plugs are different for the E engine code found on the run of the mill 5.0L Mustang, which are stock number 450.
The AGSF-32C plug Ford makes now has more thread on it compared to the original. If you want a plug that looks like the original AWSF-32C try the Autolite 764 plug. The regular 5.0L engine does call for the Autolite 25.
1993 Cobra Registry :: View topic - agsf32c motocraft plug / this stock plug for 93 cobra w/gt

also:
Plug Specs for GT-40 Iron, GT-40 Aluminum, GT-40X, & GT-40P Heads

Thread Size- 14mm
Hex Size- .625
Reach- .708
Seat type- Tapered
Electrode- Standard Nickel
Projected Tip

The stock equivalent replacement part numbers according to the Motorsport Catalog are:

Ford MotorSport Part Number AGSF-32C for the GT-40 Aluminum, and GT-40X
Ford MotorSport Part Number AWSF-32C for the GT-40P, and GT-40 Iron

These plugs cross to:

NGK - BPR6EFS Stock Number- 3623 (Stock Heat Range)

Autolite- 104

These are the NGK Race Series Part numbers and specs:

Thread Size- 14mm
Hex Size- .625
Reach- .708
Seat type- Tapered
Electrode- V-Power
Non-Projected Tip

NGK- R5724-8 Stock Number- 7317 (1 Heat Range Colder)
NGK- R5724-9 Stock Number- 7891 (2 Heat Ranges Colder)
NGK- R5724-10 Stock Number- 7993 (3 Heat Ranges Colder)
 

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Discussion Starter #18
Marunos,
I am the tech manager at Autolite and also own a 67 Mustang with a 430CI stroker windsor. I recommend using the XP103 spark plug with your heads and mods. This is just slightly colder than the stock heat range. It is a Iridium alloy fine wire spark plug with a nickel plated shell. It does cost 6.99 each at any autozone, advance or oreillys store. Why spend the money. These plugs take less voltage to fire,(giving your coil more dwell time) make a bigger flame kernal and do indeed make more power than a conventional plug. They are more resistant to pre-ignition as well. I used to run our racing plugs in my car (they are around 3 bucks each) and noticed a nice improvement in driveabilty with the XP's. You should go to our website, autolite.com and watch the autolite challenge video's, especially the first one on spark plug metallurgy and the 5th one on spark plug heat range. There is also a video on youtube about reading a plug, just search for autolite and don ward.:D
Good luck with your stang
Thank you I will need to check out the website and videos.
 

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Discussion Starter #19

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Discussion Starter #20
Well, my existing spark plugs are NGK http://www.summitracing.com/parts/NGK-7559/

The plug reach is 0.460 in. Is it why RPM hesitating when I press on accelerator?????? If I compare it to AGSF32C it is 0.708 .. maybe that NGK is too short which means cylinder will not fire properly???
 
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