1966 Rear Suspension Finishes

[Patrick H.]

Hello,

Two questions before I send parts off for plating:

1) The 1966 Judging Guide states that the rear strut rod adjusting bolt was black phosphate while the cam washer and nut were zinc. All the reproductions are zinc for all parts, and a friend says he's never seen a black adjusting bolt. So who's right?

2) The Judging Guide says the large bolts holding the rear spring to the differential are black phosphate, and that's my thought, too. Yet reproductions are currently zinc. Are the repros wrong (and yet another case of getting close but not quite)?

Thanks,

Patrick

[Craig S.]

Re: 1966 Rear Suspension Finishes

Patrick - the original GM bolts on my 67 were black phosphate when I removed them. Rusty on the exposed areas, but, the threaded section in the rear end cover was indeed black phosphate. They had the original head markings....Craig

[Joe L.]

Re: 1966 Rear Suspension Finishes

Patrick-----

1) The ORIGINAL strut rod camber adjusting bolts and cams were as follows:

bolt----------------------black phosphate

cam (part of bolt assembly)------NATURAL STEEL

cam (seperate)-------------------zinc plated

nut------------------------------black phosphate

The 1975+ style PRODUCTION bolt/cam assembly, GM #458979, which also became the
63-74 SERVICE part, was entirely zinc plated, bolt and cam.

2) The ORIGINAL and ALL GM SERVICE 9/16" spring attaching bolts were black phosphate. Most original bolts had an "indented" head; later SERVICE bolts were not so-configured.

[Patrick H.]

Re: 1966 Rear Suspension Finishes

Thanks Joe and Craig.

I assume that no one makes correct bolts in the black bolt/natural cam combination. Figures. Of course, pulling them apart and redoing them in this style is very difficult, at best.

Patrick

[Joe L.]

Re: 1966 Rear Suspension Finishes

Patrick-----

As far as I know, no one reproduces the bolt/cam assembly with the original finishes. The "reproduction" parts are the 75-79 style, although even that part is GM-discontinued.