"HD" Rear Axle Caps / Straps 427???

[Jamie F.]

Okay on page 88 of the 68-69 guide it states; "It is believed that "Heavy Duty" indicated the type of universal-joint caps and through bolts; the unmarked ratios use U-shaped clamps.
I have a late '69 (11/20) which says I should use '70 codes. My stamping is CAW which is the posi 3:08 for a 427. It does not show "HD" for this on the list like the CAX right below it.
I have a very original L68 car and everything is correct on it for a 427 except it has the U-straps on the carrier housing instead of caps. NOW my question is,,, someone did change the ratio to a 4:10 gears sometime in the last 40 years. Did they "lose" the original caps when making the swap, or did the car come with U-straps as the guide may indicate??? Should I put the caps on it or leave the straps???
Thanks in advance for the wealth of knowledge that you all bring!

[John H.]

Re: "HD" Rear Axle Caps / Straps 427???

Jamie -

Someone else can address the code/ratio issue, but you can't just "put caps on it"; to use the bolted caps, you'll have to remove and tear down the diff and change the yokes to the bolted (threaded) type.

[Jamie F.]

Re: "HD" Rear Axle Caps / Straps 427???

Yes, I know that. I was going to return it to the original 3:08's and would like to know what I should do about the yokes.
thanks!

[Harmon C.]

Re: "HD" Rear Axle Caps / Straps 427???

I have found if you think the part is not original and you are having the ratio changed I would have it restored to match the judging standard. On the judging field you will have enough headaches why add more.

[Jamie F.]

Re: "HD" Rear Axle Caps / Straps 427???

That is kinda my point. The guide is saying that only HD have the caps, and my code CAW is for a posi 427 but doesn't say "HD". Soooo depending on the judge they could interpret that it should not have caps. Couldn't they? Or shouldn't they???

[Joe L.]

Re: "HD" Rear Axle Caps / Straps 427???

Okay on page 88 of the 68-69 guide it states; "It is believed that "Heavy Duty" indicated the type of universal-joint caps and through bolts; the unmarked ratios use U-shaped clamps.
I have a late '69 (11/20) which says I should use '70 codes. My stamping is CAW which is the posi 3:08 for a 427. It does not show "HD" for this on the list like the CAX right below it.
I have a very original L68 car and everything is correct on it for a 427 except it has the U-straps on the carrier housing instead of caps. NOW my question is,,, someone did change the ratio to a 4:10 gears sometime in the last 40 years. Did they "lose" the original caps when making the swap, or did the car come with U-straps as the guide may indicate??? Should I put the caps on it or leave the straps???
Thanks in advance for the wealth of knowledge that you all bring!

Jamie-----


All 1965-74 Corvettes with big block used the stub axles with "cap" type u-joint attachment. So, if the car was originally equipped with a big block, it was originally equipped with "cap" type, "HD" stub axles. Period.

"STRAP" type attachment was NEVER used for any 63-79 stub axles. However, U-BOLT type attachment was used for all 63-68 small blocks and many 69-79 small blocks. STRAP attachment was used for the DRIVESHAFT u-joints for 68-70 with THM-400 as well as virtually all 71-79.

Some 1970 and later small blocks as well as, POSSIBLY, some 1969 small blocks did use the cap type, "HD" stub axles.

[Jamie F.]

Re: "HD" Rear Axle Caps / Straps 427???

Thanks Joe for the clarification! I appreciate it.
Any idea on the HD designation on some of the 427 pose rear ends, and not on others???

[Joe L.]

Re: "HD" Rear Axle Caps / Straps 427???

Thanks Joe for the clarification! I appreciate it.
Any idea on the HD designation on some of the 427 pose rear ends, and not on others???

Jamie-----


I think it's just an error that was created long ago, perhaps by GM, and it has been repeated and quoted many times since in documents based upon the original incorrect information.