#1  
Old 03-07-2019, 10:52 AM
Yellow Bird Yellow Bird is offline
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Default Motor mount Help!!!

The picture numbering the bolts comes from Hitman of the left motor mount. It fits perfectly. The other picture came from the service manual produced by 78TA.COM, L.L.C The left mount lines up with the bolt holes. The right one (service manual picture) only lines up with the bolt holes if I turn the mount upside down. Its the original 400 engine going back into my 77 T/A. Can anyone provide me with correct information for both sides? Should I drill another hole in my motor mount to line up the one upper hole? Is it OK to just leave the bolts the wrong way? Should I worry about engine torque? HELP PLEASE ... Can't get the picture right side up. sorry
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  #2  
Old 03-07-2019, 03:20 PM
Grand73Am Grand73Am is online now
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These pics should make it clear how they go. In the top drawing, the holes to use are the lower holes labeled LS5 and L37 etc. The upper labeled LG4 are Chevy holes. You should not need to do any drilling. Something's wrong if you have to drill.

ENGINE MOUNT HOLES IN THE FRAME by grand73am, on Flickr
DSCN3257 by grand73am, on Flickr
DSCN3260 by grand73am, on Flickr
LEFT by grand73am, on Flickr
RIGHT by grand73am, on Flickr
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  #3  
Old 03-07-2019, 04:12 PM
Yellow Bird Yellow Bird is offline
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Steve, I can't thank' you enough. I've been overthinking this issue for two days. The pix's are fantastic. Again thanks. PB
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Old 03-07-2019, 04:26 PM
Grand73Am Grand73Am is online now
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You're very welcome. Glad they helped.
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Old 09-07-2019, 09:20 PM
GregM329 GregM329 is offline
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I am currently in "Motor Mount Hell" with my '79 TA. The pictures on this thread from March verified that I am currently using the correct holes, but my frame mount pin holes aren't lining up with my engine brackets. When I put it together wrong (using upper holes on one side), the spacing was 15 13/16" (center to center) and the pins went in, but engine sat at a 3 degree angle. Now, using the correct holes, the spacing is 15 1/4" and the pins aren't going to go.

Can anybody verify what the correct distance between the frame mount pin holes is supposed to be?

I'm using Ames FN621B engine mount brackets on the engine. I hope Ames will be able to help on Monday, but that doesn't do me any good on a Saturday night.

It would seem that if I am using the correct holes, it's either the frame mounts or the brackets are wrong.
  #6  
Old 09-07-2019, 09:37 PM
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Sirrotica Sirrotica is offline
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Quote:
Originally Posted by GregM329 View Post
I am currently in "Motor Mount Hell" with my '79 TA. The pictures on this thread from March verified that I am currently using the correct holes, but my frame mount pin holes aren't lining up with my engine brackets. When I put it together wrong (using upper holes on one side), the spacing was 15 13/16" (center to center) and the pins went in, but engine sat at a 3 degree angle. Now, using the correct holes, the spacing is 15 1/4" and the pins aren't going to go.

Can anybody verify what the correct distance between the frame mount pin holes is supposed to be?

I'm using Ames FN621B engine mount brackets on the engine. I hope Ames will be able to help on Monday, but that doesn't do me any good on a Saturday night.

It would seem that if I am using the correct holes, it's either the frame mounts or the brackets are wrong.
From looking at the Ames catalogue it looks like you have the wrong engine mounts that bolt to the block, their catalogue lists FN623B as the correct bracket.

The OEM GM brackets are stamped F Body and right, or left are stamped on the OEM ones. I can tell you I was fooled to thinking all of the GM brackets were the same, they're are I believe 3 different brackets depending upon which chassis you have. Even though they look similar, the spacing is different and B body won't fit in an F body chassis as the frame is wider.
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Last edited by Sirrotica; 09-07-2019 at 09:43 PM.
  #7  
Old 09-07-2019, 09:45 PM
Grand73Am Grand73Am is online now
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Quote:
Originally Posted by GregM329 View Post
I am currently in "Motor Mount Hell" with my '79 TA. The pictures on this thread from March verified that I am currently using the correct holes, but my frame mount pin holes aren't lining up with my engine brackets. When I put it together wrong (using upper holes on one side), the spacing was 15 13/16" (center to center) and the pins went in, but engine sat at a 3 degree angle. Now, using the correct holes, the spacing is 15 1/4" and the pins aren't going to go.

Can anybody verify what the correct distance between the frame mount pin holes is supposed to be?

I'm using Ames FN621B engine mount brackets on the engine. I hope Ames will be able to help on Monday, but that doesn't do me any good on a Saturday night.

It would seem that if I am using the correct holes, it's either the frame mounts or the brackets are wrong.
The question is what kind of engine are you installing? The brackets you bought are for a Pontiac engine.

If, as Sirrotica thinks, you are installing an Olds 403, you have the wrong brackets.
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  #8  
Old 09-07-2019, 10:31 PM
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FN613 is the number for 75 up to 81 for a Pontiac engine, either way I'd say you have the wrong block brackets.
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  #9  
Old 09-08-2019, 01:37 PM
GregM329 GregM329 is offline
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I'm sorry I neglected to say that I am installing a Pontiac 400. It's supposed to be a '75 block and has the four in-line mounting holes.

For some reason, the stock stamped steel brackets that bolted on the engine are not reproduced. If you find them on Ebay, they go for about $300. That's why I bought the FN621B engine brackets, which "straddle" the FN613s which bolt to the frame.

Hopefully, Ame's Engineering Deptartment will be able to provide me with the needed dimensions so I can figure out what's wrong. Thanks for the comments, and I will report back on what I learn. If I get the dimensions, we'll save them here so we will always have them.
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Old 09-08-2019, 01:47 PM
Grand73Am Grand73Am is online now
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The original brackets can found for a lot less. That's what I'd use if I were you. GM numbers 496892 and 496893. Here are some for $119 or best offer: https://www.ebay.com/itm/75-81-Ponti...gAAOSwk3NdUJ36

I looked up your brackets on Ames, and their description does say they will fit any 60-70's Pontiac v8 to a 75-81 firebird/ta, so they should work. But, sorry to say that they sure look cheaply made in the picture.
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  #11  
Old 09-08-2019, 03:33 PM
1965gp 1965gp is offline
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I used original brackets on my 72 TA with parts store mounts and had absolute hell getting the drivers side lined up. I pulled the passenger side and started over with drivers side- would not line up at all on passenger side then.

Eventually after a lot of cussing and persuading I got the passenger side in first and the drivers second. Seems I remember a few others having a similar issue?
  #12  
Old 09-08-2019, 07:13 PM
Aus78Formula Aus78Formula is offline
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There was a set of GM-approved 75-81 400 engine mount brackets being done locally, but their website is down and not sure if they arrived or not. Likewise not sure who makes the Ames version, it also doesn't show up.
  #13  
Old 09-08-2019, 09:01 PM
GregM329 GregM329 is offline
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[QUOTE=Grand73Am;6059842]The original brackets can found for a lot less. That's what I'd use if I were you. GM numbers 496892 and 496893. Here are some for $119 or best offer: /QUOTE]

Thanks for finding those for me, Steve! I hadn't shopped for them in a while. After not finding a better option, I just now bought them.

[QUOTE=Grand73Am;6059842]I looked up your brackets on Ames, and their description does say they will fit any 60-70's Pontiac v8 to a 75-81 firebird/ta, so they should work. But, sorry to say that they sure look cheaply made in the picture./QUOTE]

I'll stick with my request to try to get dimensions from Ames, if I can prove they are bad, maybe they will refund my purchase price.
  #14  
Old 09-08-2019, 09:08 PM
Aus78Formula Aus78Formula is offline
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NOS set with lots of pics

https://www.ebay.com/itm/NOS-GM-4968...-/162214107346
  #15  
Old 09-08-2019, 09:16 PM
Grand73Am Grand73Am is online now
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[QUOTE=GregM329;6059972][QUOTE=Grand73Am;6059842]The original brackets can found for a lot less. That's what I'd use if I were you. GM numbers 496892 and 496893. Here are some for $119 or best offer: /QUOTE]

Thanks for finding those for me, Steve! I hadn't shopped for them in a while. After not finding a better option, I just now bought them.

Quote:
Originally Posted by Grand73Am View Post
I looked up your brackets on Ames, and their description does say they will fit any 60-70's Pontiac v8 to a 75-81 firebird/ta, so they should work. But, sorry to say that they sure look cheaply made in the picture./QUOTE]

I'll stick with my request to try to get dimensions from Ames, if I can prove they are bad, maybe they will refund my purchase price.

You're welcome. Good luck.
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