Motor Mounts Problems - Putting in a 78 350

[Blue_Aura]

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!!

[jayoldschool]

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.

[Blue_Aura]

Originally Posted by jayoldschool

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.

No matter what I do, the front motor mount will not line up. If I bolt up one side, the other side won't line up.
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[padresag]

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

[Blue_Aura]

Originally Posted by padresag

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

I'll try that. One thing to note is that my perches are welded to the frame. I wonder if I swapped the mounts on the engine, if they would line up then.

Also, do I need the front motor mount if the two sides are good?
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[padresag]

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

[Blue_Aura]

Originally Posted by padresag

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

On a 62, there is a horseshoe motor mount that goes under the harmonic balancer. I read that if you have a torsion bar setup that you need this mount or the lower water pipe bolt will get bent.
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[MARTYZ]

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.

[padresag]

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

[Captainfab]

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.

[Blue_Aura]

Originally Posted by padresag

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

Ok, so I took out an older 350 and am replacing it with another newer 350. The PO already had the perches welded to the frame and also had the horse shoe front motor mount also. So, without it, there are still 3 points to mount the engine to (the side engine mounts, which connect to the perches welded to the frame, then the engine is bolted to the bell housing, which connects to the trans, which is mounted on the crossmember). Sound right?

With that being said, I no longer need to worry about the horse shoe mount in the front, right?

Thanks!
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[padresag]

right
ron

[Blue_Aura]

Originally Posted by padresag

right
ron

Awesome, thanks for the info!
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[packman33]

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.

[padresag]

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

[padresag]

http://www.rowand.net/Shop/Tech/Auto...issionSwap.htm
ron

[packman33]

Originally Posted by padresag

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

Thanks for the response however, I am already aware of the distance change from the 350 to 700R4 trans. What I am trying to figure out are the motor mounts. The stock motor mounts are not aligning up with the rear holes of the cross member. They only work with the front holes however the motor seems approx 2-3" too far forward due to radiator hoses not installing correctly. Are there motor mounts that align with the rear holes of the cross member that I can use with my new 350 motor (mid 70s block)??
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[padresag]

the perches are on the right sides? there is a left and right side
ron

[packman33]

Originally Posted by padresag

the perches are on the right sides? there is a left and right side
ron

Tried both. They will line up fine on the holes closest to the front of the truck, but what I noticed first were the radiator hoses not having enough spacing and being crimped in order to mount to the motor. Pushed back 2-3" they fit great, trans mounting holes line up but the motor mounts won't work with furthest rear holes.
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[Captainfab]

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.

[packman33]

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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[PGSigns]

Post pictures of your mounts.

Jimmy

[packman33]

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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[packman33]

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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[Captainfab]

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.