Hot off the photo stand (kitchen table) are three samples with hardware. My photos are labeled with what I found for year application. I do not know the Ford part number for the brackets but they are referred to in the 71 and 73 Mustang Body Manuals (pg 61 and 63). The irony is the pictures show a 64-66 type bracket, with 67 and 70 part numbers.
What I found on my 65 and 66, plus a 67 I was working on (all San Jose cars), was the following:
The tie down hardware was apparently grabbed from buckets of other hardware used on the line. The finishes I selected were determined from what was left and what the most common other items used on the assembly line. By the second time they were used any finish was lost. I assume the 68 would be the same as 67, and 70 would be the same as 69.
64-66 - brackets as shown. They had traces of black paint on the mounting surfaces hence black.
20430-S2 7/16-14X1 1/4hex gr 2. This is a common bolt used for transmission to bell housings mounting. They may be natural.
30546-S2 7/16-14X2 1/2hex gr 2. This is a common bolt used for bell housing to engine mounting. They may be natural.
374358-S8 7/16-14 nut, 0.385T, flange. This was the nut used on 64-66 bumpers.
The washers are a mystery. I used what was on the brackets, but found something similar from AMK, 2010 catalog, pg 183, B-11754.
67-68 - brackets as shown. They had no trace of paint so I gave them a light phosphate finish.
30546-S2 7/16-14X2 1/2hex gr 2. This is a common bolt used for bell housing to engine mounting.
55826-S8 7/16-14 nut, 0.425T, locking pin.
Mystery washers again.
69-70 - same hardware as 67-68 from a pair I removed from a 69 hardtop.
Jim
OOPS.
The 64-66 and 69-70 are crossed up. "Damn these eyes!" Marty Feldman as Igor,
Attachments fixed.