ConcoursMustang Forums
1st Generation 1964 1/2 - 1973 - Questions & general discussions that apply to a specific year => 1968 Mustang => Topic started by: WT8095 on May 15, 2015, 10:43:13 PM
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The original S code motor was missing from my fastback when I received it. I have almost everything I need to put a correct motor together (still need some smog pieces). I have not seen what the carb spacer arrangement is on an original car, so I'm trying to piece together what it should be. There are some inconsistencies in descriptions in the '75 MPC, which I think I now have a handle on. Is this the correct combination, working from top down:
Carburetor
Gasket: C8OZ 9447-A (.125" fiber w/brass grommets)
Spacer: C8AZ 9A589-G (.28" plastic/bakelite?)
Gasket: C8SZ 9447-A (.018"/.024" fiber)
Manifold
Car was built in SJ on 2/7/1968.
The MPC lists the spacer as "F-High Performance", in contrast to most of the other 390GT-specific parts which are listed as F("GT w/4B carb) or simply F(w/4B carb). For years I didn't notice that listing, but many parts sites list the C8AZ-G for the 390GT. I now turn to the experts for their esteemed opinion :D
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Checked a 4/68 printing of the MPC
Spacer they listed as
Carb- to spacer gasket - C8OZ-9447-A as you listed. No description other than the 1.25 thickness
Stainless - C8AZX-9A589-C - the -G didn't exist it appears (no where to be found) at that time. The letter would suggest a later revision
Spacer to intake - Same as Big Ford 390 4V and non-PI 428 carb to spacer - Number you listed is the same
Didn't find an 390 High performance wording. Likely something added in the 7 years between when your MPC was printed and when the 68 version was
Have a couple dozen pictures of plastic carb spacers but none identified by either of the part numbers we've posted.
Did check WWC to see what they listed and they showed (out of stock) a reproduction spacer that was listed for both the 390 and the 428CJ as well as 68 & 69
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Stainless - C8AZX-9A589-C - the -G didn't exist it appears (no where to be found) at that time. The letter would suggest a later revision
That's the item that's tripping me up - I've always interpreted the '75 MPC as indicating that the C8AZ 9A589-C spacer (stainless steel) was the correct one for this application. But I have not been able to find references to the -C, and sites like Mansfield and others list the -G.
Of course both part numbers, C8AZ 9A589-C and C8AZ 9A589-G are service part numbers. It's possible the service part may be entirely different from the original, as we all know. In the October 1968 Master Cross Reference List, C8AZ 9A589-C is listed as replacing C8AE 9A589-E. I can't find ANY references to that part number online!
Fordification has a reprint of TSB #85, Article 1283 - Momentary Engine Hesitation on Acceleration and/or Rough Engine Idle. http://www.fordification.com/tsb/viewtopic.php?f=3&t=519 (http://www.fordification.com/tsb/viewtopic.php?f=3&t=519) The TSB has an illustration (attached) showing "C8AZ 9A589-C (metal spacer)" which matches the number you found and the one I originally thought was correct. Of course it's a service part # too.
Since I don't have access to any S code cars other than mine, and the books and web aren't 100% clear on the subject, I'm soliciting first-hand knowledge from those who have or have worked on original S codes.
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I will check my 68 MPC tomorrow at the shop. I think I have a NOS stainless difuser, only one I've ever seen
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I will check my 68 MPC tomorrow at the shop. I think I have a NOS stainless difuser, only one I've ever seen
Super, thanks! If it's the correct piece for this application, I would love to see some photos. And then the question becomes: would you be willing to part with it? :)
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You don't see the stainless ones often. Those "fingers" in the bore sure make it stand out and memorable when comparing it to the "normal" design Ford used
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You don't see the stainless ones often. Those "figures" in the bore sure make it stand out and memorable when comparing it to the "normal" design Ford used
By "figures" are you referring to the "tabs" in the front bores as shown in the line drawing I uploaded? Does the part actually look like the line drawing? I've never seen one in photos or in person.
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By "figures" are you referring to the "tabs" in the front bores as shown in the line drawing I uploaded? Does the part actually look like the line drawing? I've never seen one in photos or in person.
Meant to write "fingers" Yes tow (approx) 3/8 x 1/2" tabs that stick into the bore - likely to mix/atomize the fuel better
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Meant to write "fingers" Yes tow (approx) 3/8 x 1/2" tabs that stick into the bore - likely to mix/atomize the fuel better
Wow, that is unusual! I'm keeping my fingers (pun intended) crossed that Tim has one!
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Fordification has a reprint of TSB #85, Article 1283 - Momentary Engine Hesitation on Acceleration and/or Rough Engine Idle. The TSB has an illustration (attached) showing "C8AZ 9A589-C (metal spacer)" which matches the number you found and the one I originally thought was correct. Of course it's a service part # too.
One thing that should be mentioned is the illustration does not show what Ford did at the assembly plants. Just the fix when the carburetor is warped (out of specifications ;)
It does provide a look at the "spacer" being discussed - thanks
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One thing that should be mentioned is the illustration does not show what Ford did at the assembly plants. Just the fix when the carburetor is warped (out of specifications ;)
Correct, good to note for those who haven't read the whole TSB. Someone (me) should post the entire thing as a separate topic. In addition to the gasket modification, it calls for enlarging a passage in the carb itself, and how this change was incorporated in carbs built after Dec. 1967. If the TSB isn't already posted in one of the forums, I'll post it.
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(http://i25.photobucket.com/albums/c74/tlea/Mobile%20Uploads/FullSizeRender-8.jpg)
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Thank you for posting the photo Tim! Now I know what the holy grail looks like :D
So, per Jeff's documentation, and having seen them before, per the TSB, and per the MPC version I have, it seems like this should be the correct spacer for a 1968 390GT. Jeff, can you (or anyone else) confirm that this is what was installed in production? Were there any alternates (i.e. bakelite or plastic) based on date or plant? I've seen a number of 390GTs at shows, but the spacer isn't visible with the air cleaner on, and I've never asked owners about the spacer. And there seems to be virtually no knowledge online other than the repro parts suppliers, who are all showing the plastic spacer. So if the stainless one is truly correct, it would be great to document it here!
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One thing that should be mentioned is the illustration does not show what Ford did at the assembly plants. Just the fix when the carburetor is warped (out of specifications ;)
It does provide a look at the "spacer" being discussed - thanks
it was a proposed fix after thought not needed for a correct restoration.
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(http://www.concoursmustang.com/forum/gallery/4/6-191015160309.jpeg)
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(http://www.concoursmustang.com/forum/gallery/4/6-191015160309.jpeg)
Thanks Jeff! I think that solidifies it pretty well, at least for my Feb. S-code. For others, it would be interesting to pinpoint when (or if) the C8AZ-G was used on S-codes.
Posting the '75 MPC info for reference.
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I recently acquired this nice used spacer from JD Larson. One of the holy grails I have been seeking for nearly 30 years! I probably would have not found the correct one or even known what it looked like if it wasn't for all of you - thank you!
The spacer came with three thin washers looped around the tag wire. They appear to be remnants of the metal grommets used in the thick gasket that goes on top of the spacer (the grommets appear to be two-piece swaged assemblies). Can someone confirm this? I have not seen a washer like this used on the carb mounting nuts, or anywhere else for that matter.
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The spacer came with three thin washers looped around the tag wire. They appear to be remnants of the metal grommets used in the thick gasket that goes on top of the spacer (the grommets appear to be two-piece swaged assemblies). Can someone confirm this? I have not seen a washer like this used on the carb mounting nuts, or anywhere else for that matter.
If they went on the spacer you might get a nice vacuum leak. Haven't seen them before and would suggest at this point not using them. Waiting to see what turns up (if ever) in the future
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If they went on the spacer you might get a nice vacuum leak. Haven't seen them before and would suggest at this point not using them. Waiting to see what turns up (if ever) in the future
I don't plan to use them, certainly not next to the spacer. I'm almost certain they are remnants of the grommets as I described, I just like to get confirmation on those sorts of things ;) They compare very closely to the grommets when I hold them side-by-side.
My guess is that the original grommets fell apart when the carb was removed from the donor engine, and whoever took it apart was being super-careful not to throw things away so they wired them to the spacer.
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Found out that the stainless steel spacer plate was factory installed on the 1968 W code 427-4V GT-E Cougars.
There is a thread on the Cougar forum, I think that it can be viewed without being a member.
https://classiccougarcommunity.com/forum/viewtopic.php?f=37&t=4217&hilit=spacer+plate+gt+e (https://classiccougarcommunity.com/forum/viewtopic.php?f=37&t=4217&hilit=spacer+plate+gt+e)
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Finally picked up the original engine for my 1968 S code fastback (It was stored at a friends house where I bought the car 7-8 years ago). After cleaning off 47 years of crud and pulling off a lot of the peripheral parts to clean and store I discovered it still had one of these stainless spacers under the carb. The only difference between mine and the ones mentioned in the Cougar thread and here is mine doesn't have anything stamped in it (Rear, Up). Just FYI, car is a really original 1968 S code GT fastback that was last on the road in 1973. Really late build Metutchen car (mid July 68, don't have the exact date handy).
Does anyone have a copy of the TSB that mentions this as the link above seems dead.
Thank's in advance, John