What's your question about poly - do you mean polyurethane as replacements?

 

I don't believe there's a question, just a picture showing a worn out OEM and a new poly.
I did an extensive part number search when I did mine and the replacement inserts were 454 BB ones, and I can't remember much more. I don't believe I found a replacement mount, just the insert, but the clam shells rarely wear out and are easy to change. IIRC from a recent thread, the BB ones are just a bit longer, but are lot heavier.

 

Do a search and make sure you get the right poly mounts, if you order the ones for a 6.5 you will get the wrong ones, if I remember right you need the ones for a 2wd 454, DO NOT use aftermarket mounts, I had to change mine twice.

 

Yes, No questions here. Just really surprised when I noticed what a bad motor mount does for engine location. After seeing pics of what the aftermarket mounts look like on the inside I would never consider having one. Energy Suspension (hard to tell with all my paint) mount inserts are the way to go! They fill the entire mount shell!

 

I'm looking forward to seeing the "out" pics...

 

What's the Energy PN you used, and what was the source/cost?

 

Motor mount pics

I took a few pics of some of the mounts I had bought...
One of the sets was from wrong advice, another set I had picked the wrong ones myself, the correct set I had called Energy Suspension directly and was given the correct number.

1st set are 3.1116
2nd set are 3.1121
3rd set are 3.1152

The 3.1152's ARE the correct 6.2 / 6.5 / 7.4 mounts

 

Motor mount pics

I took a few pics of some of the mounts I had bought...
One of the sets was from wrong advice, another set I had picked the wrong ones myself, the correct set I had called Energy Suspension directly and was given the correct number.

1st set are 3.1116
2nd set are 3.1121
3rd set are 3.1152

The 3.1152's ARE the correct 6.2 / 6.5 / 7.4 mounts

Have a question about the mounts. I’m putting a 6.2 from a g20 into a ‘75 c10. The mounts as far as I can tell are the same. My question is. Would I use the clam shells from the c10, and just replace the guts with the right poly mount? Or would I have to use the mounts from the g20 and get the poly for the g20?

 

Excellent info. Added to the 6.2 and 6.5 FAQ's

 

Amazon appears to be the cheapest source at $30ea today, but they don't think it fits my truck. I trust you more than them, though. But you could be the first to write a review there.

 

Ahhh thats why they didnt fit well. I ordered the engine and transmount kit 3-1131 kit from summit which had the 3-1121 motor mounts for a 305/350 engine. I had to take them to a bench grinder to make them fit in the shells. If I had to do it all over I would order the 3.1152s and the 3.1129 trans mounts separately.

 

for the DIY types:

More on Motor Mounts - PeachParts Mercedes ShopForum

check out posts 6 and 13

 

wicked info:thumb: how usable is this on our mounts?

 

Wish I would have checked this before I ordered the part number suggested on one of this sites sponsors website I ordered the 3.1116 mounts which are too short for the 6.5 mounts. Im ordering the 3.1152 mounts now.

 

I wanted to add to this thread. I posted previously in 2014 as "JCDiesel" but I can't get back into that account. Anyhow I just replaced the mounts on my 91 GMC 6.2 diesel NA GMT400 truck and here is the insert that rockauto listed and it fits properly (3.1121). Why it differs from what has been posted here previously I cannot tell you. I installed the 3.1152 mounts in my 94 6.5 many years ago and those fit so this alsmost doesn't make sense. In addition I do not know if the part number will be different for a square body truck because I no longer own one.
Heres a couple tips:
When opening the clamshell drill out the side (top / upper) with the two bolt holes. I put it in a vice to open the shell and install the new insert. When closing the shell using a vice the holes will not line up but using a taper punch and some vice grips works well then weld the shell back together. Before installing the inserts be certain the orientation of the metal tabs are correct so the motor will sit correctly on the mounts. Although this is a straight forward task the instructions included are helpful.

 

Ya that is a good tip about making sure you got them in the right direction. I thought of that after I had the first one back installed and I was working on the 2nd. Luckily I just happened to get it right. Would have been a big hassle to discover that when I was trying to drop the engine back in. The back in process was the one part I got help on so I would have been wasting more than just my time.

Those energy brand is what I just installed. I don't remember if I got them from Rock or Summit but was under the impression they were sold as a pair especially based on the price compared to the others where you got the steel too. They were each so look close where you are getting them from. It didn't hold up the project but could have been a delay and extra shipping costs. Turns out I had other delays and needed other parts so it wasn't that big a deal.

I'm pretty sure they transmit more vibration than even the worn out rubber ones. I was concerned about that but the alternatives just seemed to be too inexpensive to be any good. I had to swap engines so didn't want to skip it or install crap and have issues sooner than later. It was nice to put the down pipe back on and not have it hit the frame.

I didn't really see any reason to weld or replace the rivets. I was doing it with the engine out so maybe if you were doing them with the engine installed it would make a difference?

Anyone use any of the rubber ones recentlyish? Especially if you are shopping at Rock the average price is like $7 and many of them include the steel part. You can even get a 3 piece set for like $30. I know these ain't that complex but that just seems too cheap to me. One drop of diesel or oil on them and they melt? So soft you were better off with the old sagging ones? I have used some of those cheap ones for other applications where they were the only option and they did hold as long as those cars held together which wasn't that long so no idea how they would have been long term.