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#1 |
Registered User
Join Date: Aug 2012
Location: Tracy, CA
Posts: 251
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Motor Mounts Problems - Putting in a 78 350
So I was putting in the 78 4 Bolt Main, 2 piece rear seal, 350 and things are just not going well. The front motor mount does not match up at all. The previous 350 was a 68. Is the front motor mount different on a 78?
Also, I got the passenger mount lined up and a bolt in it, but the Driver's side is just a tad off, and I just cant get it to line up. I have two bolts in the bell housing on each side. It seems like the Driver's side needs to go back just a hair, but I can't get it to go back enough. I have checked and rechecked, and have tried jacking up the Turbo 350 to see if it will slide back some. So, my major questions are: 1. Do I need a different front motor mount for a 78 350? 2. Any ideas about getting the Driver's side to line up enough to get a bolt in it? Any help is much appreciated. Thanks ahead of time!!
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Current Vehicles: '62 C10 - 350 (current project), '03 Tahoe (C Series) Some Past Projects: '69 Nova - 350 , '70 1/2 Camaro Z28 - LT1 350, '73 K20 Full-time 4x4 - 400 SB, '77 1/2 Camaro Z28 - 350, '84 Camaro Z28 - 305, '68 Buick - 430 BB |
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#2 |
Moderator
![]() Join Date: Dec 2012
Location: ON, Canada
Posts: 2,159
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Re: Motor Mounts Problems - Putting in a 78 350
Mounts should be the same. I always find it easier to put in an engine and trans bolted together. You get a floor jack under the tail shaft of the trans and that will help line up the engine as you lower it.
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#3 | |
Registered User
Join Date: Aug 2012
Location: Tracy, CA
Posts: 251
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Re: Motor Mounts Problems - Putting in a 78 350
Quote:
Posted via Mobile Device
__________________
Current Vehicles: '62 C10 - 350 (current project), '03 Tahoe (C Series) Some Past Projects: '69 Nova - 350 , '70 1/2 Camaro Z28 - LT1 350, '73 K20 Full-time 4x4 - 400 SB, '77 1/2 Camaro Z28 - 350, '84 Camaro Z28 - 305, '68 Buick - 430 BB |
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#4 |
Registered User
Join Date: Feb 2008
Location: Sidney,b.c.
Posts: 4,425
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Re: Motor Mounts Problems - Putting in a 78 350
try slacking off on all of the bolts esp where the perches mount to the frame and crossmember. that should give you some wiggle room. thake the weight off the mounts so that you can just move them
ron |
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#5 | |
Registered User
Join Date: Aug 2012
Location: Tracy, CA
Posts: 251
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Re: Motor Mounts Problems - Putting in a 78 350
Quote:
Also, do I need the front motor mount if the two sides are good? Posted via Mobile Device
__________________
Current Vehicles: '62 C10 - 350 (current project), '03 Tahoe (C Series) Some Past Projects: '69 Nova - 350 , '70 1/2 Camaro Z28 - LT1 350, '73 K20 Full-time 4x4 - 400 SB, '77 1/2 Camaro Z28 - 350, '84 Camaro Z28 - 305, '68 Buick - 430 BB |
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#6 |
Registered User
Join Date: Feb 2008
Location: Sidney,b.c.
Posts: 4,425
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Re: Motor Mounts Problems - Putting in a 78 350
by frt motor mount are you talking frt timing cover area?. if you are installing a 350/350, you require the 2 side mounts on the side of the eng block and the one under the rear of the trans.
those perches shouldn't be welded in. it removes the possibility of being able to move them like I suggested, but is easier to install if it works ron |
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#7 | |
Registered User
Join Date: Aug 2012
Location: Tracy, CA
Posts: 251
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Re: Motor Mounts Problems - Putting in a 78 350
Quote:
Posted via Mobile Device
__________________
Current Vehicles: '62 C10 - 350 (current project), '03 Tahoe (C Series) Some Past Projects: '69 Nova - 350 , '70 1/2 Camaro Z28 - LT1 350, '73 K20 Full-time 4x4 - 400 SB, '77 1/2 Camaro Z28 - 350, '84 Camaro Z28 - 305, '68 Buick - 430 BB |
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#8 |
Registered User
![]() Join Date: Mar 2012
Location: Shallow Lake Ontario,Canada
Posts: 201
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Re: Motor Mounts Problems - Putting in a 78 350
I would suggest cut the welds and get the perch mounts bolted in way they should be, leave the bolts loose until motor installed and then tighten everything up. had to do that with mine when put the small block in.
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#9 |
Registered User
Join Date: Feb 2008
Location: Sidney,b.c.
Posts: 4,425
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Re: Motor Mounts Problems - Putting in a 78 350
orig on your truck y6ou had the horseshoe mount on the frt and the side mounts off the bellhousing. that gave you 3 point mounting which is what you require. now if you have the side eng mounts and perches and the rear trans mount you will have a 3 point mounting which is what you require. forget about the horseshoe mount - not required.
the motor should be in exactly the same position unless you screwed up putting(welding in) in the side perches if you don't get it show us some pictures of your mounting so that we can see what you have done ron |
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#10 |
60-66 Nut
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Location: Coeur d'Alene, Idaho
Posts: 23,248
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Re: Motor Mounts Problems - Putting in a 78 350
You do not need the front motor mount in addition to the side motor mounts. It is just either the front or side mounts. However with a auto trans you must have side motor mounts. The motor mount brackets you have on the sides don't sound to be original. Just eliminate the front mount and see if everything bolts up. Having the front mount is actually working against you. There is no physical difference between a '68 small block and a '78 small block.
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#11 | |
Registered User
Join Date: Aug 2012
Location: Tracy, CA
Posts: 251
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Re: Motor Mounts Problems - Putting in a 78 350
Quote:
With that being said, I no longer need to worry about the horse shoe mount in the front, right? Thanks! Posted via Mobile Device
__________________
Current Vehicles: '62 C10 - 350 (current project), '03 Tahoe (C Series) Some Past Projects: '69 Nova - 350 , '70 1/2 Camaro Z28 - LT1 350, '73 K20 Full-time 4x4 - 400 SB, '77 1/2 Camaro Z28 - 350, '84 Camaro Z28 - 305, '68 Buick - 430 BB |
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#12 |
Registered User
Join Date: Feb 2008
Location: Sidney,b.c.
Posts: 4,425
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Re: Motor Mounts Problems - Putting in a 78 350
right
ron |
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#13 |
Registered User
Join Date: Aug 2012
Location: Tracy, CA
Posts: 251
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Re: Motor Mounts Problems - Putting in a 78 350
Awesome, thanks for the info!
Posted via Mobile Device
__________________
Current Vehicles: '62 C10 - 350 (current project), '03 Tahoe (C Series) Some Past Projects: '69 Nova - 350 , '70 1/2 Camaro Z28 - LT1 350, '73 K20 Full-time 4x4 - 400 SB, '77 1/2 Camaro Z28 - 350, '84 Camaro Z28 - 305, '68 Buick - 430 BB |
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#14 |
Junior Member
![]() Join Date: Sep 2015
Location: Bluffdale, Utah
Posts: 30
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Re: Motor Mounts Problems - Putting in a 78 350
I am having a similar issue but let me mention where I am at. I took out what I believe to be the original 350 4-bolt main block with 350 auto trans in my 70 C20. I had a newer (mid 70's) 350 4-bolt built to my specs and I also chose to have a rebuilt 700R4 tranny installed. The motor mounts that were used previously are not currently lining up with the further rear holes in the cross member mount, which after researching are supposed to be used with all V8 motors? I'm seeing conflicting pictures of this as when I look for new sbc motor mounts they are using the cross member holes closer to the front of the truck. So which holes am I supposed to use? If I use the ones closer to the front of the truck then the motor visually looks to be too far front, the radiator hoses crimp and don't fit right, along with none of the holes on the trans cross member lining up. When I push the motor back, motor visually looks better (distributor closer to firewall), radiator hoses fit nice, however the motor mount holes do not line up. Do I have the wrong motor mounts for my mid 70's block to mount to my 70 c20 cross member or is there something else I am doing wrong? I will mention that the mounts I took out appear to be original (mirror type) with the two holes that bolt to the frame, one center bolt to the rubber mount, then one bolt that goes to the cross member. I believe the mounts were originally bolted to the front holes of the cross member, which again conflict with some research I have done and the rear holes of the cross member will not bolt to the mounts I currently have.
Thanks for any help you can provide. Last edited by packman33; 03-13-2017 at 05:22 PM. Reason: verbage |
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#15 |
Registered User
Join Date: Feb 2008
Location: Sidney,b.c.
Posts: 4,425
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Re: Motor Mounts Problems - Putting in a 78 350
check the distance on you a/trans between the th350 and the 700r4 for the distance from the front of the trans to the rear trans mount. they are not all the same
ron |
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#16 |
Registered User
Join Date: Feb 2008
Location: Sidney,b.c.
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Re: Motor Mounts Problems - Putting in a 78 350
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#17 | |
Junior Member
![]() Join Date: Sep 2015
Location: Bluffdale, Utah
Posts: 30
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Quote:
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#18 |
Registered User
Join Date: Feb 2008
Location: Sidney,b.c.
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Re: Motor Mounts Problems - Putting in a 78 350
the perches are on the right sides? there is a left and right side
ron |
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#19 | |
Junior Member
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Location: Bluffdale, Utah
Posts: 30
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Quote:
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#20 |
60-66 Nut
![]() ![]() Join Date: Mar 2007
Location: Coeur d'Alene, Idaho
Posts: 23,248
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Re: Motor Mounts Problems - Putting in a 78 350
With the '67-'72 trucks the factory engine mount brackets for a small block bolt into the front sets of holes in the frame and crossmember. The 230/250 I6 engine mount brackets bolt into the rear sets of holes in the frame and crossmember. The brackets for the small block and the I6's are not the same bracket and are not interchangeable. The engine mounts themselves are the same from '63-'72 for the I6's and the small blocks.
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#21 |
Junior Member
![]() Join Date: Sep 2015
Location: Bluffdale, Utah
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Thank you. This helps and conflicts with other research I have done however I agree with you. Is it possible with my mid 70s 350 motor that it changed the alignment of the mounts or are these mounts on the mid 70s block the same? I still feel the motor is not sitting in the correct position while the current mounts are mounted to the front subframe holes. Thank you.
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#22 |
Senior Member
![]() Join Date: Jan 2011
Location: Hayes Va
Posts: 4,569
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Re: Motor Mounts Problems - Putting in a 78 350
Post pictures of your mounts.
Jimmy
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60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic |
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#23 |
Junior Member
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Location: Bluffdale, Utah
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Re: Motor Mounts Problems - Putting in a 78 350
I will use the front set of holes then. However, I'm still at a loss as to why the motor (mid 70s) seems too far forward at that location. Distributor is a good distance away from fireball, radiator hoses crimped a bit. Any ideas?
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#24 |
Junior Member
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Location: Bluffdale, Utah
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Can someone give me the measurement from their firewall to the center of the distributor cap? Trying to figure out how far forward the motor should be. Again, my truck is a 70 C20 2wd auto Thanks.
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#25 |
60-66 Nut
![]() ![]() Join Date: Mar 2007
Location: Coeur d'Alene, Idaho
Posts: 23,248
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Re: Motor Mounts Problems - Putting in a 78 350
All small block Chevys have the engine mount location the same from 1957 thru 2002. In the '67-'72 trucks with a small block in the stock location, do appear that the engine is too far forward.
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Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE |
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