# 69 GTO Motor Mounts 455 Engine



## dmpgto (Jun 12, 2016)

Hello,All knowing ones .I searched a few of the motor mount questions from years gone by but still have a question about Motor Mount Brackets.. A couple years ago I put a 73 455 in my 69 gto and up until lately thought the reason my oil pan was rubbing on my center link was a larger urethane tranny mount tipping the engine forward slightly .....not so. Just discovered a well known fact (not to me of course) (73) 455 blocks motor mounts same height. (69) 400 staggered with the pass side lower. My question is can I run (2) of the 69 tall brackets to equalize the height and use the pre-drilled holes At least until I can pull my motor and re drill for 455 mounts I assume the holes for the 455 brackets wont line up with the already drilled 400 mount holes. If you guys have run into this and know what I need to do.... please share!!!


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## Pinion head (Jan 3, 2015)

Beginning in July of '69, Pontiac v8 blocks began having 5 bosses on each side of the block,drilled and tapped for attaching either of two styles of motor mount. The upcoming 2nd Gen Birds with Pontiac V8's as well as '70-72 factory 455 Abodys, all 71-76 B bodies, all used the long style motor mount which attached to the side of the block with 3 bolts. 350 and 400 Pontiac engines in Pontiac A bodys continued to use the shorter two bolt motor mount through the '72 model in conjunction with the '64-72 326-400 Pontiac A body frame strands.

The issue of the centerlink rubbing the oilpan is fairly common. Its unnecessary to change over to repro 455 A body frame stands, mounts, and longer cross through bolts. One of several issues is causing the interference, and the problem has to be addressed:

-thicker (taller) trans crossmember mount...very common (you've eliminated this)
-slight depression in pass side frame cradle crossmember from TONS of miles and heavy engine torquing over.
-frame cradle sag, often combined with above.
-cheap replacement import oilpan which does not have correct depression at the front.
-goofy trans swaps, like making a long tail T400 "fit" by moving trans crossmember back and drilling new holes, I've personally witnessed this contraption "rig" in bkth '70 and '71 Pontiac A body's...causes stock fan to rub lower fan shroud. Throws off inclination of driveshaft and correct pinion angle.

Below is an earlier discussion where I mention solving the engine interference issue by making steel spacers to go under the stock frame stands. I've always made the spacers out of 1/8" steel plate, not 1/4" plate. Using a spare drivers side stand on the passenger side, is going to raise the engine too much in my opinion. have to carefully, ESP if car is equipped with manual transmission/clutch linkage

.http://www.gtoforum.com/f12/69-gto-motor-mounts-102657/


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## dmpgto (Jun 12, 2016)

Gold... Ive struck Pontiac Gold.. Thank you I am going to order up a new set of frame plates.(mine a a little worn) break out the 1/8" steel and let the games begin. Since I swapped for the Art Carr 200R4 no Carnage underneath .I thought there was an indentation on the front of the original oil pan.Googled it to try and find an image no luck but i remember it. Thanks for your help


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## bnreed3 (Apr 18, 2016)

Oh man, this is the same issue I have. I have a 455 from a 75 trans am in my 69 GTO. The engine is not level and is lower on the passenger side. I have it in the shop right now actually. What is it exactly that I should tell my mechanic to order/machine?


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## Pinion head (Jan 3, 2015)

there are 3 bolts/ nuts that hold each triangular frame stand to the front frame crosssmember. Each of the nuts and lock washers can be on top or one or two can just have the head of the bolt on top. At a minimum, going to have to lift the engine, remove the pass front side tire/wheel & shock. The fun part is "forking" each bolt head or nut, up though the frame. Years ago, i heated and bent and ground on old distributor wrench to make a tool that will get up in there. it's a whole lot easier to access when replacing front springs. after you get the passenger side frame stand out, you can trace the outline on a piece of cardboard, then use the cardboard as a template on 1/8" plate steel. Cant remember examining a frame that needed more than an 1/8". If the block is cocked in at such an angle that it needs to be raised 2+ inches on the pass side... you have other problems. I would start to diagnose by taking measurements from each frame horn to a level floor. Would also measure from the frame to the level floor at front of the center side rail of each side of the frame. Would also ck the condition of the coreupport mounting holes, as well as the core support mtg bushings.


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## bnreed3 (Apr 18, 2016)

Pinion head said:


> there are 3 bolts/ nuts that hold each triangular frame stand to the front frame crosssmember. Each of the nuts and lock washers can be on top or one or two can just have the head of the bolt on top. At a minimum, going to have to lift the engine, remove the pass front side tire/wheel & shock. The fun part is "forking" each bolt head or nut, up though the frame. Years ago, i heated and bent and ground on old distributor wrench to make a tool that will get up in there. it's a whole lot easier to access when replacing front springs. after you get the passenger side frame stand out, you can trace the outline on a piece of cardboard, then use the cardboard as a template on 1/8" plate steel. Cant remember examining a frame that needed more than an 1/8". If the block is cocked in at such an angle that it needs to be raised 2+ inches on the pass side... you have other problems. I would start to diagnose by taking measurements from each frame horn to a level floor. Would also measure from the frame to the level floor at front of the center side rail of each side of the frame. Would also ck the condition of the coreupport mounting holes, as well as the core support mtg bushings.


Thanks, Pinion. I uploaded a picture of the engine bay to my album if you want to take a look. It seems to be cocked at a larger angle than 1/8". Is it not safe to stack 1/8" steel plates? I did forward your email to my mechanic and he agrees a 1/8" plate won't be enough to bring it flush. I asked him to check the mounts on the drivers side to make sure there aren't any washers, etc that are hiking that side up more than it needs to be. If you have any other recommendations please let me know. I hope there aren't larger issues here :|

Pinion, I found this from you in an earlier post with a guy wanting to do the same thing to his '71 GTO..."In the '64-72 Pontiac A body's , only '70 factory optioned 455 GTO's along with and '71 & '72 Pontiac A body's with factory installed 455's used the specific 455 frame brackets and the long style motor mounts. The '70-72 455 A body frame brackets were bringing over $500 a pair till they were reproduced nearly 10 years ago. if you like you can swap over to the $160 repro 455 frame stands, and run the longer mounts, but it's not required, a '64-69 326-428 or any '70- mid 76 Pontiac v8 will bolt in using the standard '64-72 Pontiac A body frame stands." 

If I were to purchase the $160 repro frame stands with the longer mounts for the passenger side would it take care of the problem?


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## Pinion head (Jan 3, 2015)

bnreed3, Hello! looked at the pic in your album. Without lifting the engine up, possibly even removing the engine, examining the motor mounts, and laying a flat steel rule across the passenger side of the crossmember, it's going to be very hard to diagnose what's wrong. When the engine torques over, it's typically the driver side rubber/steel mount that will eventually tear apart. After several hundred thousands of miles of hard use, typically on '64-72 Abodys with long time use of the the highest torque engines, one can observe some fatique of the steel where the steel motor mount stands bolt in. Pulling the engine up, your mechanic can look at the surface of the crossmember. He will first, most likely, note that it will be very tight getting a socket onto the head of the pass side motor mount bolt. Have run into this many times. The steel in this crossmember area has been pushed inwards some by the many many years of of the engine torqueing over. That is where I've found an 1/8" steel plate spacer can help. 

On Performance Years forum, there was a fellow in the last year selling lazer or water jet cut out 1/4" spacers to go under the 326-400 style engine mount stands. My own experience is once one starts going really thick on the spacers, the pick up point for the motor mounts narrows too far. Over the last 25 years, I have pulled literally hundreds of clean frames out of southern A-body part cars. i have yet to run across a frame that the stock mounted engine was cocked to the passenger side at an extreme. Two of my '71 Pontiac 233's & one of my '72's are factory 455 HO cars. Have also owned several more '70-71 455 GTO's, and am very acquainted with the 455 frame stands. Nearly 15 years, actually modified a few '70-71 Firebird V8 engine stands into a very close facsimile of the the then very expensive factory 455 A body frame stands. Joe at the Parts Place recognized the crazy prices original 455 A body stands were going for, and thus he had repro 455 stands made for restorers, solely a profit driven venture, IMHO. Going to Joe's repro 455 frame stands and accompanying style motor mounts will do little to change the inclination of your engine. There may be a very slight lowering on the drivers side, as the drivers side 455 frame stand is not as tall as the 326-400 frame stands. Bright and early in the AM, I will measure the height of both styles of engine frame stands, have a pair of 455 stands out of one of my '72's, as well as a pair of the 326-400 A body stands. Can drop you a PM later in the day if you like with pics and measurements.


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## Stan's Customs (Jan 27, 2007)

Pinion head said:


> bnreed3, Hello! looked at the pic in your album. Without lifting the engine up, possibly even removing the engine, examining the motor mounts, and laying a flat steel rule across the passenger side of the crossmember, it's going to be very hard to diagnose what's wrong. When the engine torques over, it's typically the driver side rubber/steel mount that will eventually tear apart. After several hundred thousands of miles of hard use, typically on '64-72 Abodys with long time use of the the highest torque engines, one can observe some fatique of the steel where the steel motor mount stands bolt in. Pulling the engine up, your mechanic can look at the surface of the crossmember. He will first, most likely, note that it will be very tight getting a socket onto the head of the pass side motor mount bolt. Have run into this many times. The steel in this crossmember area has been pushed inwards some by the many many years of of the engine torqueing over. That is where I've found an 1/8" steel plate spacer can help.
> 
> On Performance Years forum, there was a fellow in the last year selling lazer or water jet cut out 1/4" spacers to go under the 326-400 style engine mount stands. My own experience is once one starts going really thick on the spacers, the pick up point for the motor mounts narrows too far. Over the last 25 years, I have pulled literally hundreds of clean frames out of southern A-body part cars. i have yet to run across a frame that the stock mounted engine was cocked to the passenger side at an extreme. Two of my '71 Pontiac 233's & one of my '72's are factory 455 HO cars. Have also owned several more '70-71 455 GTO's, and am very acquainted with the 455 frame stands. Nearly 15 years, actually modified a few '70-71 Firebird V8 engine stands into a very close facsimile of the the then very expensive factory 455 A body frame stands. Joe at the Parts Place recognized the crazy prices original 455 A body stands were going for, and thus he had repro 455 stands made for restorers, solely a profit driven venture, IMHO. Going to Joe's repro 455 frame stands and accompanying style motor mounts will do little to change the inclination of your engine. There may be a very slight lowering on the drivers side, as the drivers side 455 frame stand is not as tall as the 326-400 frame stands. Bright and early in the AM, I will measure the height of both styles of engine frame stands, have a pair of 455 stands out of one of my '72's, as well as a pair of the 326-400 A body stands. Can drop you a PM later in the day if you like with pics and measurements.


 This is an old post I know...but it would really help if those frame stand measurements were posted on the forum rather than a PM. If anyone has these measurements...I would really appreciate knowing what they are.
Seems like Pontiac information is scarce...and inaccurate much of the time when you do find something.
I'm working on a 69 GTO that has everything new...core support, motor mounts, trans mount(4 speed), body mounts, fan shroud and mounts, water pump...you name it. The fan sits 4 inches below the bottom of the Ames fan shroud....?????
I guess the motor itself is way low...but the clutch linkage looks good thru the Hooker header tubes. Gota be careful here or the clutch linkage can be an issue as stated above.
Any help, from anywhere, would be really appreciated. Thanks...Stan M.


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## O52 (Jan 27, 2019)

Sounds like the core support or transmission support/mount is installed incorrectly.


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