1965 GT350 spark plug wire

[SCOTTGTK]

Folks, need you help... in 1965, GT350's came with a red boot or black boot spark plug wire? Looks like per the 289 High Performance Mustang book (Tony Gregory, 4th edition) that they came with black boots... Thanks for your help!  Scott

[Bob Gaines]

Folks, need you help... in 1965, GT350's came with a red boot or black boot spark plug wire? Looks like per the 289 High Performance Mustang book (Tony Gregory, 4th edition) that they came with black boots... Thanks for your help!  Scott

65 boots were typically black . It wasn't until 1966 production where the higher temperature resistant silicone based reddish boots started to get introduced.

[SCOTTGTK]

Thank you Bob.... can you recommend a good, correct brand?

[Bob Gaines]

Thank you Bob.... can you recommend a good, correct brand?

Besides original the ones Marti sells about the only game in town as far as I know. FYI the 65 GT350 typically came with radio resistance wires from the factory not the SX steel core.

[SCOTTGTK]

Ok, I'll check out Marti...is the 289 High Performance Mustang publication incorrect stating 65 GT350 came with "SX" and numbered for is corresponding cylinder as well as non resistence? Part number C5ZZ 12259 A   Page 38 and 39. 4th edition.

[Bob Gaines]

Ok, I'll check out Marti...is the 289 High Performance Mustang publication incorrect stating 65 GT350 came with "SX" and numbered for is corresponding cylinder as well as non resistence? Part number C5ZZ 12259 A  Page 38 and 39. 4th edition.

At least as it relates to GT350's it is incorrect. There is typical and not typical. If you do any research there are so many vintage magazine GT350 engine photos that confirm the radio resistance wire is the typical it makes it hard to question which is typical and which is not typical. Easy to tell even from a distance where it is hard to read the difference is in length of the words "Radio Resistance" vs "SX".  By contrast try to find vintage photos of GT350's that have the SX wire  . FYI this applies to 65-67 GT350's. It was common for decades for people to switch out the stock wires for SX steel core ones because they were perceived as correct or the high performance expectation. Another example of commonly switched out items because of the high performance expectation, Koni shocks on all year Shelby's when they were only used stock on 65 and 66's up to vin 900. In concours the the SX wires are typically a deduction unless you can come up with reasonable proof that they were used on that particular car. 

[Dan Case]

SX was a maker's mark logo for Essex Wire Corporation. The ink stamped SX is a plain text representation of the maker's logo printed or in some cases metal stamped somewhere on every electrical item Essex Wire made for Ford Motor Company in the mid-1960s

Note the artistic SX logo stamped into the Ford FDD-14303-A grounding cable assembly ring terminal.


I found this corporate logo online.

[Dan Case]

Before the 1965 model year some 427 Ford engines were exempt from Civil Defense radio interference rules from ignition systems and used what Ford described as "wire" cored secondary ignition cable sets. 1963½-1964 High Performance 289 engines were also allowed to used wire core cable sets. The last documented to date 1964 HP289 engines were made July 11, 1964. Almost immediately 1965 model year engines went into production. Ford indicated that all 1965 model year engines had radio resistant secondary ignition wiring with what they described as "linen" core sets. Bob Mannel covered this topic in more detail in his online book. When 1965 MUSTANG GT350 SFM5R002 was first completed as a race car it used radio resistant secondary ignition wire as shown in the original Sports Car Graphic photograph set. Bob's book also mentions dealers sometimes swapping in wire core sets to satisfy owner complaints.

Yes, some five bolt HP289 engines manufactured as 1964 model year engines late May 1964 through July 11, 1964 went into early "1965" Mustangs (plus 1964 Fairlanes and 1965 Cobras) . Just saying 1965 Mustangs with HP289 engines does not separate out the early cars with five bolt 1964 HP289 engines and most with 1965 HP289 six bolt engines.

In a direct quote from a publication sent to dealers for the 1965 sales season (service parts). (Bear in mind that service items were often different than assembly line versions in many cases. Here, I do not know one way or the other.):

FORD 289 HIGH PERFORMANCE ENGINE GENERAL PARTS USE
 
63    C3AZ-12259-F    Spark Plug Wire Set - Steel Core (Fairlane) - 4V                        9.00
64    C4OZ-12259-F    Spark Plug Wire Set - Steel Core (Fairlane) - 4V                      10.00
65    C3OZ-12259-H    Spark Plug Wire Set - Linen Core (Fairlane, Mustang) - 4V      7.50

I have no idea what might have been different between the C3AZ-F and C4OZ-F sets unless it was the coil wire assembly. Service parts wise in the time frame, there were a linen core (1 version) and wire core versions (3) available to dealer service departments in the same document as above. Fairlane parts also applied to Cobras.

Ford also had a over the counter service set.
65    C5ZZ-12259-A    Spark Plug Wire Set - Steel Core (Fairlane, Mustang) - 4V      10.00

[SCOTTGTK]

It appears the set Marti sells is not radio resistance, unless I'm not looking close enough?

[Rickmustang]

They sell three different sets

[Bob Gaines]

Or NPD sells Marti products and is typically faster shipping .    https://www.npdlink.com/product/spark-plug-wire-set-concours/101413

[Bob Gaines]

It appears the set Marti sells is not radio resistance, unless I'm not looking close enough?

You may be looking at what they refer to as Hipo wires. The spark plug wires are not hipo unique for 65-67. Much of the aftermarket has yet to catch up to the most up to date information on this subject.  Regular Mustang radio resistance wires are factory original on your 65-67 GT350.

[s2ms]

Also, Marti can custom make whatever you want, such as steel core wires with a radio resistance cover, and vice versa. It may cost 2x-3x more, thought they used to offer some combinations direct from the website. They made me a custom steel core/radio resistance cover set in 351W lengths to match the cam firing order. Only took about a week.

[Bob Gaines]

It should be noted that steel core wire should be only used with a minimum amount of modern electronics because of electrical interference. Things like pertronix ignitions,radio and or CD to name a few can be adversely affected by the interference.

[SCOTTGTK]

I am running pertronix, but have no other electronics other than electric fuel pump.... radio is out... at the end of the day, I just want the best wire for my original, matching # Kcode that looks/is correct for 65 GT350.Opinions?