VancouverL71

Hopefully someone can shed some light on my engine mount frustration.
Fristly, my car is an early 1969 big block 427 L71 corvette. Original frame no modifications.
Just about ready to put in my rebuilt engine so just test fitting a few things. I looked at the original mounts (Mount 1) in picture and decided it made sense to replace them.

So shame on me for ordering on line after some research a very good quality Energy Suspension poly engine mount (Mount 2) in the picture which said big and small block chev (first mistake). Although the bolt pattern to the engine was correct, it was to tight to fit onto the frame.

So next in interest of saving time I go to my local auto shop and the counter guy order's 2 engine mounts for 1969 corvette big block 427. Today I pick them up and bring them home to test fit (Mount 3) in picture. though they looked very similar to my originals, they don't fit either. Again too small to fit over frame mount. Shame on me twice.

I measure from ear to ear on the mount and my original mount is nearly 2 and 3/4" while the new ones are both 2 and 3/8" between the ears that slip over the frame.

Can someone shed some light on what is going on. Does the weight of the engine open these mounts up to fit properly or have I just twice ordered the wrong size engine mount.

Thanks for any ideas, I am beyond frustrated at this one.

Pete



All three mounts

Original mount

Energy Suspension mount

Anchor mount made in the USA

Bob K

Here are pictures of the motor mount that I got from Paragon. They fit great on my '70 frame that is going under a '72 with a 496.

Bob K.

DUB

CORVETTE CENTRAL sells the correct type and I just put a pair in a 1979 and they fit like a glove and NO PROBLEMS in getting them to work.

Now the motor mount I used are the later design withe safety catches on the mount. Photo below and the link to it

https://www.corvettecentral.com/c3-6...ts%26count%3d9


Now the link below and photo are the motor mounts that do not have the safety catches on them.


https://www.corvettecentral.com/c3-6...ts%26count%3d9


DUB

Bob K

Mine were also the later style. No need to put the air cleaner into the hood.

Peterbuilt

Got my locking mounts at the local parts store, here are the measurements:

VancouverL71

Thanks so much Bob, Dub and Peterbuilt. I really appreciate the quick responses. Obviously I have purchased the wrong items. Will take these last ones back and if I can't get them from my local source, I will order online.
Again, Thank you gentlemen

Sayfoo

I had the same problem with my 69/427 about 10 yrs ago. Went to PepBoys, AZ, and O'Reileys. All had the same Anchor brand like you show and the same part # and none fit. I needed the wider ones.
Finally, I took the old ones with me and a parts guy matched them up. He said they were listed for a '58 Impala.
I think that there were only a few different ones used in your year range, so it should be easy to match up.

Rescue Rogers

i bought mine from Summit racing, no problems

VancouverL71

DUB

I have done the same thing but I use the special shaped washer off of the old motor mount due to the slot in those washer is needed so you can index the engine block on the frame due to not each and every motor mount perch spacing is in the same location on each and every corvette the same. I weld them in and then grind them to the thickness I need.

DUB

Sigforty

Whoever ordered the energy suspension mounts got the wrong ones. There are two sizes the 2-5/8 Part #3.1114G and the 2-3/8 Part #3.1117G

VancouverL71

Thank you Dub,

I wil fabricate a washer with the oval slot inside to take consideration for any tolerance. Just a quick question which has me a bit puzzled. The slot means there will be some play in the mount which I would expect could cause vibration. Do I therefore torque the mount very tight so ensure no movement once the engine is in place? Any idea what torque? If I ever do a second corvette this will all be much simpler but this is the first crack at all these issues for me so I try to limit my amature questions.

It was me Sig, thanks for your response. It wasn't obvious when I ordered the mount so I wish I had asked the question beforehand! Thanks for letting me know, I will try to send them back for the 3.1114G in return. If they arrive in time for my engine install I will use the Energy Suspension poly version instead as I presume they are superior.

DUB

I have run into the polyurethane engine mount needing to have the holes for the bolt that goes through it to hold it to the frame be off and not sit down as far as an original. And by opening up the holes... so much of the metal is taken away from it ...it makes be concerned if it is stout enough o work...but it seems to hold up on the few cars that had those type of engine mounts put in them.

And this is on a mount that will fit down on a the perch. ...so it is the correct width.

DUB

Dynra Rockets

This topic comes up a couple times a year. Search the forum for "Safety mounts"

https://www.corvetteforum.com/forums...or-mounts.html

Starting in 1970 there are "safety" mounts for big blocks that are wider at the frame mount. Aftermarket manufacturers now use a common stamping for both and then use a washer (or user supplied washer) as a spacer to make up the width for the safety mount.