69 Z/28 engine stands

[TODD]

While restoring the 69 Z I replaced the motor mounts with units from Year One. After sending back the 69 Z mounts and calling the tech line/service
I was told some of the early cars had 68 Z/BB mounts, maybe until newer version release or supply was used up? Can any of you early 69 guys confirm? My 69 is a 68 built 10E car. Anyhow I have looked at the mounts a few times and
wonder why 68 style? The 68's are wider tower with engine mount containing spacers welded on right? I seem to remember the 69 style motor mount being too narrow to fit the wider 68 style tower? Also I'm pretty darn sure these towers are original, they looked like the original hardware had not been removed when I pulled the engine out.
 
 Next question; Do the modern style engine mounts I purchased contain a built in rubber isolater stop-lift fastening device?
By this I'm talking about the engine lift brackets I see on e-pay all the time. Seems in the first gen cars the mounts would break loose
and the accelerator would fully engage with disasterous results.
I'm pretty sure some of the newer design non-original mounts I've seen have a metal tab retainer built in them to provide break-away engine retainment.
Do the newer original style mounts incorporate a fastening device engineered through them to prevent this problem right?
Why is everyone insistant on providing stop-lift brackets on a restored car? Is it for motor mount retainment on original restored cars?
I'm a little worried if mine might not come loose at some point. If they aren't for retainment then why?
If these parts would be correct then why shouldn't every TSB part be installed for us anal-retentive correct guys?
Was this a major recall or just a TSB.

Todd

[william]

Hoo boy.

For 1969 Chevrolet used 2 sets of frame brackets and corresponding motor mount for small-block engines: 327 & 307 use the 67-68 small block brackets and non-interlock mount, 302 & 350 used frame brackets designed for the new interlock motor mount. The 302/350 brackets are shorter and narrower than the 67-68 brackets. The '69 interlock motor mount will not fit on the 67-68 frame bracket but the non-interlock mount will unfortunately fit [loosely] on the 69 frame brackets. If you do this expect clutch chatter and driveline vibration, the engine will be about 1" too low in the chassis.

Complicating the issue is the fact that service replacement 67-68 style motor mounts now have the interlocking feature. The best way to figure out what mount you need is to measure the width of the frame brackets and get motor mounts that are the same inside width-the correct mount is a tight fit on the stand. The 67-68 mount is about 1/4" wider than the 69 interlock frame bracket.

For the record SB & BB do share motor mounts but not frame brackets.

[PACE&Z2869]

Hello. Your reply to TODD as far as the clutch chatter and driveline vibration is exactly what my 69 z/28 that i just finished (98 miles and 2 weeks ago) is experiencing. I now wonder if my local GM dealer sold me the wrong engine mounts? These mounts have the interlocking feature and are original GM mounts. William you mentioned that the service replacment mounts for 67 and 68 also now have the interlock. I'll check for that 1/4 inch gap that you refered to in your reply that might exist if I have the wrong mounts. William could you or anyone else provide the correct p/n for rubber engine mount (GM) for 69 z/28, and also 67-68 p/n to see if I indeed do have the wrong mounts. Thank you in advance.

[william]

A couple of other signs you have the wrong mounts are the balancer very close to the stabilizer bar and the #5 spark plug right next to the PS gear.

The mounts have changed #s over the years. You need 69 302/350 or 69 396/427 mounts, same thing.

I learned this the hard way 30 years ago with a 69 Z/28.

[TODD]

William;
 Guess I'll need to send some pic's, but everything fits and functions correctly.
Non-interlock mount will fits tight on frame bracket.
No #5 spark plug issue. (non-ps car so ?)
and the balancer clears the sway bar with room to spare.
Weird
Todd

[william]

Check for BB crossmember. Should have SB. Creates a different alignment problem.