1966 Clutch rod jam nuts

[Joe L.]

Re: Addendum

Mike-----

It goes against the intuitive, but it might be true. If it is true, it's like saying that in the case of a Chevy head bolt, as long as you have 7/16" of thread engagement, you don't need any more. Of course, head bolt tappings in blocks are not hardened.

In any event, in the case of these clutch rod jam nuts, the reported nuts used were 7/32" thick. So, that makes them quite a bit thinner than the thread diameter (3/8").

[Joe L.]

Re: Addendum

Mike-----

It goes against the intuitive, but it might be true. If it is true, it's like saying that in the case of a Chevy head bolt, as long as you have 7/16" of thread engagement, you don't need any more. Of course, head bolt tappings in blocks are not hardened.

In any event, in the case of these clutch rod jam nuts, the reported nuts used were 7/32" thick. So, that makes them quite a bit thinner than the thread diameter (3/8").

[Wayne M.]

How did that thread on the Dark Side end up ?

John -- back in July, Michael Hanson asked me about the nut thicknesses on my '65s. He said thinking was that sometime during the '65 MY that the nuts went from 2 thin to one thick (forward) and a thin (on the firewall side of the swivel).

I reported that my early '65 has 2 thin, but my late car has 2 thick (IMO this means little as several Bubbas owned over the years). BUT, #23563 and Tony Stein's # 233xx were both not driven since 1973, and they both have the thick lower and the thin upper.

1965 TIM&JG of course calls for 2 thin. What do '66 and 67 manuals say ?

BTW, never realized that these same nuts were also on the BB rear sway bar linkage. Just confirmed by checking my 396. No evidence of any bright plating on any of the unrestored 2 thick and 8 thin nuts (incl. a grungy '64 push rod & swivel) that I have.

[Wayne M.]

How did that thread on the Dark Side end up ?

John -- back in July, Michael Hanson asked me about the nut thicknesses on my '65s. He said thinking was that sometime during the '65 MY that the nuts went from 2 thin to one thick (forward) and a thin (on the firewall side of the swivel).

I reported that my early '65 has 2 thin, but my late car has 2 thick (IMO this means little as several Bubbas owned over the years). BUT, #23563 and Tony Stein's # 233xx were both not driven since 1973, and they both have the thick lower and the thin upper.

1965 TIM&JG of course calls for 2 thin. What do '66 and 67 manuals say ?

BTW, never realized that these same nuts were also on the BB rear sway bar linkage. Just confirmed by checking my 396. No evidence of any bright plating on any of the unrestored 2 thick and 8 thin nuts (incl. a grungy '64 push rod & swivel) that I have.

[John H.]

Re: How did that thread on the Dark Side end up ?

Wayne -

There are two ways to approach this. If you go by the Engineering specs and part numbers in the '63-'67 A.I.M's, the same two thin nuts were used from '63-'67, as the part number never changed during that period.

However, as our lengthy survey and long thread about six months ago on VH board indicated, the plant deviated from specs and began using one thin and one thick nut in '65, then two thick nuts, and in most of '66 and all of '67 all had two thick nuts, both phosphated.

Production guys like what works best for them

[John H.]

Re: How did that thread on the Dark Side end up ?

Wayne -

There are two ways to approach this. If you go by the Engineering specs and part numbers in the '63-'67 A.I.M's, the same two thin nuts were used from '63-'67, as the part number never changed during that period.

However, as our lengthy survey and long thread about six months ago on VH board indicated, the plant deviated from specs and began using one thin and one thick nut in '65, then two thick nuts, and in most of '66 and all of '67 all had two thick nuts, both phosphated.

Production guys like what works best for them

[Wayne M.]

Thanks, John; missed the conclusions

on VH site. And MH reminds me that I have it backwards (thin nut forward, regular nut to firewall side of swivel -- pic below is of 65 #23563; sitting since 1973) What was I thinking ?

So you're saying that #23564 with 2 thick nuts MIGHT also be factory ? It still has its unique L78 upper clutch pushrod.

[Wayne M.]

Thanks, John; missed the conclusions

on VH site. And MH reminds me that I have it backwards (thin nut forward, regular nut to firewall side of swivel -- pic below is of 65 #23563; sitting since 1973) What was I thinking ?

So you're saying that #23564 with 2 thick nuts MIGHT also be factory ? It still has its unique L78 upper clutch pushrod.

[John H.]

Re: Thanks, John; missed the conclusions

Wayne -

I think the two thick nuts are probably factory; during my 38 years in assembly plants, I've seen LOTS of "deviations", both authorized and not. I can still recall many I made in 1964

[John H.]

Re: Thanks, John; missed the conclusions

Wayne -

I think the two thick nuts are probably factory; during my 38 years in assembly plants, I've seen LOTS of "deviations", both authorized and not. I can still recall many I made in 1964