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Username Post: Motor mount question.        (Topic#237537)
1sick57 
Forum Newbie
Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-11-10 02:44 PM - Post#1878267    

I just spent hours searching for the correct 350 motor mounts for a G-body. There are frame mounts, engine mounts, inserts, etc. What I cant find is how the engines are actually mounted! My guess is that there is a metal clamshell bracket bolted to the engine, which fits over the motor mount itself which is bolted to the frame. Is this correct? Does anyone maybe have a picture?



 
GSMCSW 
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Posts: 21

Loc: OHIO
Reg: 10-14-07
03-11-10 04:48 PM - Post#1878342    
    In response to 1sick57

Yes, this is correct. I don't have pics rite now. The inserts will listed as 3 or 4 bolt mount, 73-77 G bodies use a 4 bolt. The only cars I've seen use the 3 bolt is a trans am. good luck, Ron

76 Laguna S-3, 454/700r4
79 Chevy, K30, Dually
76 chevy, Suburban, 57k miles
74 chevy, Nova, 383/350


 
1sick57 
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Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-11-10 06:09 PM - Post#1878407    
    In response to GSMCSW

Thanks for that, I guess I need to find them used since they don't turn up on the internet.



 
67SS427 
Ultra Senior Member
Posts: 12692
67SS427
Loc: Lawrenceville, GA, USA
Reg: 05-26-01
03-11-10 09:08 PM - Post#1878539    
    In response to 1sick57

I guess you have a Monte Carlo? What year?

The engine mounts are different for 73-74. They have the rubber mount on the engine and then they sit on a metal perch bolted to the frame with a bolt thru them.

The 75-77 is the opposite of that. They use "clamshell" motor mounts. The clamshell mount has the rubber mount inside and bolts to the frame. Then there's some metal brackets that bolt to the engine which sit over the clamshell mounts and a long bolt goes thru them. This setup is better than the 73-74 type.

If you have a 75-77 Monte, and you have no mounts at all, you need to find some used engine brackets for a 75-77 Chevelle(or Malibu), or Monte Carlo. You might find some on eBay.
Then you buy some new motor mounts from the auto parts store for your application and a couple of long grade 8 bolts and nuts to go thru the mounts. I think they're 1/2" size bolts, but it's whatever is a good fit thru the brackets. And you'd need enough 3/8" bolts and nuts to fasten the mounts to the frame and the brackets to the engine.






 
monte-77 
Member
Posts: 889
monte-77
Loc: Western New York State
Reg: 06-04-06
03-12-10 03:30 AM - Post#1878594    
    In response to 67SS427

When we did the resto on one of our 75 Lagunas, we found motor mounts at the local Advance Auto store.

Dave

Takin' care of business.

77 Monte Carlo, 75 Laguna S-3, 77 Malibu Classic, 84 Impala, 98 Z34 Monte, 16 Equinox, 2011 Impala, 06 Pontiac Grand Prix, 95 Monte Carlo Pace Car

http://www.hemmings.com/hcc/stories/2010/12/0 1/hmn...


 
1sick57 
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Age: 62
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03-12-10 06:10 AM - Post#1878650    
    In response to monte-77

Well thanks to everyone! It's a umm, err, let's call it a 1977 "Monte Carlo"(Grand Prix). And I think I've got it figured out. It's like Steve says, the motor mount is on the frame, with a clamshell bracket on the motor. I'm putting the drive train from a 9C1 caprice into the Grand Prix, and a Google image search reveals that the motor mounts are exactly the same as a Monte Carlo, (or Grand Prix). It never ceases to amaze me how interchangeable some GM cars are! I'm beginning to think that I could bolt in the entire drivetrain and running gear from the Caprice into the Grand Prix!



Edited by 1sick57 on 03-12-10 06:16 AM. Reason for edit: No reason given.

 
67SS427 
Ultra Senior Member
Posts: 12692
67SS427
Loc: Lawrenceville, GA, USA
Reg: 05-26-01
03-12-10 08:04 AM - Post#1878696    
    In response to 1sick57

To be clear, the clamshell is the motor mount on the frame. They call it a clamshell because it's a metal enclosure that holds the rubber mount inside.
The part that's bolted on the engine is just a metal bracket that will slip over the top of the clamshell mount, and you put the bolt through.

Here's an illustration from a pontiac parts manual. The green arrow points to the engine bracket. Since you're using a Chevy engine, you need Chevy engine brackets, and you probably have to use a pair from a 75-77 Chevelle or Monte Carlo for everything to fit right. And the clamshell mount is the #1 in the picture:








 
1sick57 
Forum Newbie
Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-12-10 08:47 AM - Post#1878707    
    In response to 67SS427

Steve, the motor mount on the frame in that diagram looks like the one I bought yesterday for a '76 Monte Carlo, which has the same part number as the one for a '94 Caprice!



 
67SS427 
Ultra Senior Member
Posts: 12692
67SS427
Loc: Lawrenceville, GA, USA
Reg: 05-26-01
03-12-10 12:57 PM - Post#1878846    
    In response to 1sick57

Interesting. The later Caprice chassis does share alot of interchange with the 73-77 A and G body frames. So, maybe the brackets on the Caprice engine will work. Certainly they will fit the motor mounts since the mounts are the same number.
The only other thing I'd wonder is whether the height of the Caprice brackets is the same as 75-77 Chevelle/Monte brackets, so they will locate the engine at the right height for the car.

If we had the GM part numbers for the brackets, we could tell if the 94 Caprice engine bracket is the same part number as a 77 Chevelle/Monte engine bracket. Unfortunately I don't have a Chevrolet parts catalog that covers those years.






 
1sick57 
Forum Newbie
Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-13-10 04:58 AM - Post#1879169    
    In response to 67SS427

You bring up an interesting point, I'm going to try to find a part number, picture, or actual car to see if they're different. Thanks for all your help!



 
1sick57 
Forum Newbie
Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-13-10 05:53 AM - Post#1879195    
    In response to 1sick57

I found a picture of the engine mount brackets, they don't appear to be tall.



http://www.montemania.com/images/nosgenuinegmpa rts...



 
Randy_W 
None
Posts: 27804

Reg: 01-06-02
03-13-10 08:34 AM - Post#1879283    
    In response to 1sick57

The whole deal should be a bolt in, on my Firebird LT1 swap, I used one clam shell from the Impala SS and one from a late eighties pickup, because for some reason the Impala one wouldn't clear the rubber on one side. The mounts are Camaro on mine. The '73-'77 frame is pretty much identical to the later full size. Some combo should bolt up with no mods. The LT1 uses a different bolt hole arrangement on the right side because of the a/c compressor. But it's all compatible. When I put the LT1 in my '67 Impala SS I used '67 mounts.

Randy

DON'T mess with Old Men, we didn't get old by being, STUPID!!!

"The veneer of civilization is very thin!" (Arlo)


 
1sick57 
Forum Newbie
Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-13-10 10:03 AM - Post#1879331    
    In response to Randy_W

Yay!



 
Rob Wheatley 
Member
Posts: 29

Loc: Calgary, Alberta
Reg: 10-30-04
03-13-10 01:16 PM - Post#1879420    
    In response to 1sick57

Here are some part numbers.

0.027 Mounting, Engine (Attaches to frame)
73-74 all (350) 6262215
74 all (400) 6262215
75 all (350) 6262232
75 all (400) 6262232
73-75 chevelle (454) 334941
76 A,B,F (V-8) (Exc. 454) 357716
77 A,F (305, 350) 357716
77-78 A (305, 350L) 467472
(I have no idea why two different part numbers are listed for 1977.)

0.029 Bracket-support, Engine Mounting (Attaches to engine)
73-75 Chevelle (350) 334970
74-75 Chevelle (400) 334970 (only R.H. listed ???)
73-75 Chevelle (454) 334962
76 A,X (V-8) 334970
77-78 A,B,X (350, 350L) 334970

I'm rather surprised that mounting an engine (that doesn't change--excluding the 454) to a frame (that doesn't change) would change so much.
Rob



 
67SS427 
Ultra Senior Member
Posts: 12692
67SS427
Loc: Lawrenceville, GA, USA
Reg: 05-26-01
03-13-10 01:42 PM - Post#1879440    
    In response to Rob Wheatley

Thanks for posting those numbers!

Looks like the engine brackets(except big block), are the same 73-77, so it looks like the clamshell mount setup was used in all those years of Chevelle.

I was thinking 73-74 was the different earlier type of setup, but that must just be Pontiacs.






 
76guna 
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Posts: 49
76guna
Loc: Denton
Reg: 05-20-09
03-13-10 04:55 PM - Post#1879549    
    In response to 67SS427

i've found if you leave the bolts on both sides loose until you get them all started it makes it much easier to get the long bolts installed.

Link

1976 Laguna S-3
1991 Lincoln Mark VII (Dart-NOS-3:73)
1996 KTM 620 RXCe
2005 Scion TC


 
1sick57 
Forum Newbie
Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-13-10 06:28 PM - Post#1879605    
    In response to Rob Wheatley

Thanks Rob, it will be interesting to see what the part numbers are on the engine mounting brackets of the LT1.



Edited by 1sick57 on 03-13-10 06:29 PM. Reason for edit: No reason given.

 
1sick57 
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Posts: 14

Age: 62
Loc: Lyons
Reg: 02-28-10
03-14-10 05:18 AM - Post#1879777    
    In response to 1sick57

This from the Chevrolet Small Block V-8 Interchange Manual:

From 1968 to 1972 solic steel receiver brackets were bolted in place on the frame. The mount on the engine had rubberized construction that was prone to failure. For this reason, in 1973 Chevy engineers developed the steel engine bracket and rubberized frame mounts. These mounts (part number 459021) are universal throughout the Chevrolet car lines; the B, A, G, F and X small-block equipped cars all have the same internally rubberized pieces bolted to the frame.

The steel brackets bolted to the engine from 1973 to 1988 differ slightly in length so it's important to get the correct pieces for the vehicle you have. The 1973-76 B body GM cars use the longer bracket (part number 334601); all other 1973 and later GM cars use the shorter bracket (part number 334970)



 
jb2wheeler 
Valued Contributor
Posts: 4340

Loc: Louisville KY
Reg: 05-09-04
03-14-10 06:11 AM - Post#1879803    
    In response to 1sick57

I assume this thread will be made a "sticky". JB

If you can't hum it, it ain't music! http://www.picturetrail.com/gallery/view?p=999&am p...


 
Blazerteam 
Member
Posts: 261

Loc: Norway
Reg: 03-17-05
08-08-10 01:49 AM - Post#1957347    
    In response to jb2wheeler

  • jb2wheeler Said:
I assume this thread will be made a "sticky". JB




It should..im in the process of installing a 454 in the Chevelle these days,and i began wondering about those clamshells...they are diffrent on a 454 than on a 350...so now i need to modify some 350 ones for my 454..should be interesting .But as long as the mounts in the frame has the same location bb and sb wise,i think im gonna make that work.



Edited by Blazerteam on 08-08-10 01:51 AM. Reason for edit: No reason given.

 
bitterfitter 
Contributor
Posts: 525

Reg: 05-18-08
08-08-10 02:50 PM - Post#1957659    
    In response to Blazerteam

I just dropped my engine in my car today and it went right in. I used the motor mounts I had from another engine. I used PN# 334971 on the drivers side and PN# 14039436 on the passenger side. Motor sits nice and the mounts lined up great. I dropped a 350 into a 1974 malibu classic by the way.



 
Blazerteam 
Member
Posts: 261

Loc: Norway
Reg: 03-17-05
08-09-10 08:25 AM - Post#1958039    
    In response to bitterfitter

  • bitterfitter Said:
I just dropped my engine in my car today and it went right in. I used the motor mounts I had from another engine. I used PN# 334971 on the drivers side and PN# 14039436 on the passenger side. Motor sits nice and the mounts lined up great. I dropped a 350 into a 1974 malibu classic by the way.




I had to mount the small block clamshells on a 454 block to measure the diffrence..on a center line between the bolts for the frame mounts,i measured a half inch diffrence between the small block and the bigblock with the same clamshells...

That wasnt much,so i will try to use the clamshells as is,and see if they work..



 
Techgirl7 
Forum Newbie
Posts: 1

Reg: 11-12-17
11-12-17 07:19 PM - Post#2714203    
    In response to Blazerteam

Did anyone have any luck with this? My Dad is dropping a 454 in to a 73 Malibu and we are struggling to find the right solution since the bracket support appears unobtainable.

73-75 Chevelle (454) PN 334962. Does anyone happen to have a picture of this part?

He is itching to drop the engine in, but we haven't found a good solution to mount it.



 
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