1975 Jack date -- is C 5 proper?

[Bob B.]

The jack in my 75 Convertible appears to be the original, bought car from original owner / collector

The jack is stamped C 5 the judging guide #2 page 19 says it should be number for the year followed by a letter for the month (eg 5M for Dec 75) jack appears proper in all other aspects. In one old post by Joe I think Ausco quite building jacks in 73
How about a bit input here is that C 5 stamp OK or ???
THANKS,
Bob Brewer #967 3/31/75 build date 75 Convertible L-82 red

[Tom R.]

Re: 1975 Jack date is C 5 proper

The jack in my 75 Convertible appears to be the original, bought car from original owner / collector

The jack is stamped C 5 the judging guide #2 page 19 says it should be number for the year followed by a letter for the month (eg 5M for Dec 75) jack appears proper in all other aspects. In one old post by Joe I think Ausco quite building jacks in 73
How about a bit input here is that C 5 stamp OK or ???
THANKS,
Bob Brewer #967 3/31/75 build date 75 Convertible L-82 red

Yes! There is a revision team working to update the 75-77 manual and it concluded that Stant jacks (SMP logo) do not appear until 1976. 1975s were still equipped with the Ausco jacks using the date format you described. In fact, the manual uses a C5 jack to illustrate the date code.

Jack date code_75_C5.jpg

[Bob B.]

Re: 1975 Jack date is C 5 proper

EXACTCTLY same as mine including bum stamp of the 5 picture in old JG is a black blur. THANKS, I have been away from my 75, sidetracked on my '70 "driver" restoration in CALIF back in TN with the 75 how is the work on the new JG coming, got to be a monster project
Bob Brewer #967

[Tom R.]

Re: 1975 Jack date is C 5 proper

EXACTCTLY same as mine including bum stamp of the 5 picture in old JG is a black blur. THANKS, I have been away from my 75, sidetracked on my '70 "driver" restoration in CALIF back in TN with the 75 how is the work on the new JG coming, got to be a monster project
Bob Brewer #967

Love to see a photo of that C5...high resolution preferred.

We took off Jan 1, 2020 and the team has gone through exterior, interior and now working on Chassis but got sideliined on some mechanical topics that came up that were of interest to the revision team. It is a project. We are learning that emission control systems presented a difficulty to engineers and the Corvette brand wathe last to get attention due to low volume sales. So this resulted in lots of changes we are plowing through.

For example, and you can help with this, it appears that 75s with M40 were equipped with a secondary choke-pull off device that hung off the backside of the carb and its sole role was to lock the secondary out from opening during cold start. Apparently four-speeds were not equipped th and it was 75-only thing. The question to you...is do you have it and then what power team does your 75 have?

choke_secondary_lockout.JPG

[Tom R.]

Re: 1975 Jack date is C 5 proper

I should add, the current manual is just over 100 pages. The 3rd edition will be in excess of 250 pages with over 600 colored photographs and technical detail never before seen in the current version. Much was missed when the 1st rolled out over 20 years ago as well has not fully understood, the nuances of production from one year to the next. We include footnotes for additional information that while, not judge-centric stuff, is worth noting. The table of contents are expanded and accompany each section...no other manual does this except the 73/74 that came out last year. So you can see lots of enhancements...worthy of the new pricing.

As another example with your 75, over the last few days, we have discussed the unique one-year only air cleaner. The backside is dented to allow for space to accommodate the HEI distributor. Also, the lid has a compact rubber O-ring whose role is to "silence" the rush at hard acceleration that activates the solenoid and opens the vent at the back of the hood. That O-ring is not present i 73-74 air cleaner lids but then it carriers forward into 1976-81 or whatever is when it changed again.

[Bob B.]

Re: 1975 Jack date is C 5 proper

This is a close up of he date on my 75 Convertile L82 auto vin 1Z67T5S420824 3/31/75 BUILD BOB #967
IMG_0796.jpg

[Bob B.]

Re: 1975 Jack date is C 5 proper

IMG_0672.jpgIMG_0672.jpgIMG_0663 (1).jpg

[Guy F.]

Re: 1975 Jack date is C 5 proper

I should add, the current manual is just over 100 pages. The 3rd edition will be in excess of 250 pages with over 600 colored photographs and technical detail never before seen in the current version. Much was missed when the 1st rolled out over 20 years ago as well has not fully understood, the nuances of production from one year to the next. We include footnotes for additional information that while, not judge-centric stuff, is worth noting. The table of contents are expanded and accompany each section...no other manual does this except the 73/74 that came out last year. So you can see lots of enhancements...worthy of the new pricing.

As another example with your 75, over the last few days, we have discussed the unique one-year only air cleaner. The backside is dented to allow for space to accommodate the HEI distributor. Also, the lid has a compact rubber O-ring whose role is to "silence" the rush at hard acceleration that activates the solenoid and opens the vent at the back of the hood. That O-ring is not present i 73-74 air cleaner lids but then it carriers forward into 1976-81 or whatever is when it changed again.

Sorry for the confusion I created here Tom. The '75 lid is the same as the '73/'74 lid. The '75 with K50 (low noise air cleaner) had a different lid with an (assumed ) rubber o-ring seal around the periphery of underside of the lid, which seals the lid to the air cleaner base, like that of the '76-'81 air cleaners. This rubber o-ring seal would be inside the outer lip of the underside of the lid, and is not to be confused with the flange seal which seals the air cleaner to the underside of the hood.

Thank you,

[Tom R.]

Re: 1975 Jack date is C 5 proper

Sorry for the confusion I created here Tom. The '75 lid is the same as the '73/'74 lid. The '75 with K50 (low noise air cleaner) had a different lid with an (assumed ) rubber o-ring seal around the periphery of underside of the lid, which seals the lid to the air cleaner base, like that of the '76-'81 air cleaners. This rubber o-ring seal would be inside the outer lip of the underside of the lid, and is not to be confused with the flange seal which seals the air cleaner to the underside of the hood.

That's funny and I understood that but what's correct then is the 73/74 lid becomes an assembly in 75 with the addition of the rubber O-ring. So the K50 lid is an assembly...lid and O-ring. Words matter don't they but we see the value of the forum here to tease out these mis understandings. If I'm in error here do let me know.

[Guy F.]

Re: 1975 Jack date is C 5 proper

The jack in my 75 Convertible appears to be the original, bought car from original owner / collector

The jack is stamped C 5 the judging guide #2 page 19 says it should be number for the year followed by a letter for the month (eg 5M for Dec 75) jack appears proper in all other aspects. In one old post by Joe I think Ausco quite building jacks in 73
How about a bit input here is that C 5 stamp OK or ???
THANKS,
Bob Brewer #967 3/31/75 build date 75 Convertible L-82 red

Bob,

To answer your question "C 5" is a correct date stamp for your jack. My '75 jack for the build date March 20 (F20) has a "C 5" stamp. Tom posted a picture of it earlier.

Thank you,

[Bob B.]

Re: 1975 Jack date is C 5 proper

I APPRECIATE YOUR INPUT Thanks, Bob

Bob,

To answer your question "C 5" is a correct date stamp for your jack. My '75 jack for the build date March 20 (F20) has a "C 5" stamp. Tom posted a picture of it earlier.

Thank you,

[Bob B.]

Re: 1975 Jack date is C 5 proper

That's funny and I understood that but what's correct then is the 73/74 lid becomes an assembly in 75 with the addition of the rubber O-ring. So the K50 lid is an assembly...lid and O-ring. Words matter don't they but we see the value of the forum here to tease out these mis understandings. If I'm in error here do let me know.

HOW IS THE NEW JG COMING ALONG 75-77 ? THANKS Bob Brewer

[Tom R.]

Re: 1975 Jack date is C 5 proper

I got a note that it showed up at Frisco