Joe, I know this has been discussed at length, but I'm working on an issue that I have. After 40K miles of ownership(car now has 148,000mi)and a fairly worn out L-82 w/automatic, I installed that GM '73-'85 replacement 350ci 4 bolt in my 1975 coupe along with a "correct" & "correct dated" '75 Borg-Warner Super T10. I bought this "complete kit" from a reputable Corvette dismantler for a good price, however some of the pieces seem to be "mix-match" type deal. The bellhousing is dated 3/'81 and I'm certain it's of Corvette origin as is the clutch linkage related parts too. The only real "issue" I have is I was sent a 10.4" flywheel, which I believe '75-'81 4 speed cars took 11.0" flywheels. I ended up having to get a Borg-Warner clutch kit for a '72 LT-1 as that kit contained the 10.4" pressure plate and a 26 tooth "fine-splined" disc. Now the issue. I've put many a GM Chevelle, Camaro & Corvette clutches together, but this "set-up" has way too much pedal/linkage travel BEFORE the throwout bearing even touches the diaphram fingers of the pressure plate. Matter of fact, the back of the clutch fork wants to hit the bellhousing before the disc can spin free. Maybe the 10.4" pressure plate is not as "TALL" as a 11.0 plate, which why I may have too much "room". I may have to go with the "long" style throwout bearing(the kit came with the short style) OR a longer pivot stud. I'm not sure of the length of the stud in my bellhousing. Aren't there "3" different lengths of "pivot studs" from GM??? Supposedly '55-'81 Corvettes ALL used only ONE length??? Thanks for your help.
-
-
Re: Joe Lucia; Clutch Pivot Stud GM Part #'s...
Paul-----
There are actually quite a few different ball studs that were used over the years on various applications. However, many of these have different thread than the style used for Corvettes and cannot be used with a Corvette (and many other Chevrolet) bellhousing. Also, most of these are discontinued, anyway.
1955-1981 Corvettes actually used 2 different ball studs. 1955 through 1963 used a 1-1/2" stud of GM #3729000. 1964 through early 1975 used a 1-3/8" stud of GM #3887159. Later 1975 through 1981 again used the 1-1/2" 3729000. The 3887159 was discontinued from SERVICE many years ago and was replaced by the 1-1/2" 3729000.
There is at least one other stud available that I believe will fit the Corvette bellhousing. This stud is GM #3790556. Unfortunately, I don't know the length of this stud. I sort of doubt that it will solve your problems.
To aid in getting this situation "sorted out", what is the casting number of the bellhousing that you are using and what is the casting number of the flywheel that you're using.
A few things:
1) I know of no 10.4" flywheel. However, a 12-3/4" flywheel is used with the 10.4" clutch
2) All 69-81 Corvettes originally used a 14" flywheel with an 11" clutch EXCEPT
----69 w/MA-6 and 71 LS-6 (these used 14" flywheel with 10" dual disc clutch)
----69 L-88/ZL-1 (these used 12-3/4" flywheel with special 10.4" clutch)
----70-72 ZR-1 (these used 12-3/4" flywheel with special 10.4" clutch)
----78-79 with L-48 (these used 12-3/4" flywheel with 10.4" clutch)
3) All 1957-81 Corvette used the SHORT clutch release bearingIn Appreciation of John Hinckley -
Re: Joe Lucia; Clutch Pivot Stud GM Part #'s...
Joe, Thanks again for the help. I guess what I meant on the flywheel was that it accepts the 10.4" pressure plate. I had a complete used 11.0" pressure plate set-up that was the original clutch out of my old Yellow '80 4spd, which had a BW Super T-10 and it was "too large" for this flywheel. I seem to recall the flywheel had a casting date of D 12 8, so it's probably a "68" flywheel. I'll look into getting that #3790556 stud, they're relatively cheap. I also believe if worst comes to worst, I have plenty of room in there for the "long style" throwout bearing. Thanks again, Paul Borowski, Massillon, OhioComment
-
Re: Joe Lucia; Clutch Pivot Stud GM Part #'s...
Paul-----
If it's a 68 flywheel and of 12-3/4" OD, then it should work alright with your engine and it should work alright with your clutch disc and pressure plate assuming that you have the correct disc and pressure plate. All 10.4" clutches are not the same. Regardless, for it to work assuming that all the internal parts are correct, the bellhousing has to be either a '383' or '403' bellhousing. I don't know of any other that will work.
If you are using one of these bellhousings, a correct Corvette clutch fork (all 64-81 are the same), the 68 12-3/4" flywheel, the 1-1/2" ball stud, and a correct clutch/friction disc, then the short release bearing should work perfectly. If you have to use a longer ball stud and/or release bearing, then the clutch you have must not be the correct one. In that case, I'd change it for the correct one rather than modify other components of the assembly (like the ball stud and/or release bearing).In Appreciation of John HinckleyComment
Comment