Good motor mounts... how about this?

[L31MaxExpress]

You must be registered for see images attach

Not even close to correctly-made. Poly insert is too wide, and the steel tangs molded-into the Poly are at the wrong angle.

I would argue the factory rubber is too narrow. The poly fit my brackets from the Van and the Tahoe like a glove and the angles were right for it. Absolutely zero issues setting the engines in.

 

[L31MaxExpress]

The poly mounts have been in the van for ~8 years. I pulled the brackets apart. Cleaned them up and shot them with some paint along with the crossmember before the engine went back in.

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[L31MaxExpress]

On mine they fit fine and the steel tangs interlocked correctly. They are slightly bigger and make for a tighter fit, but mounted ok in the steel clamps.

You must be registered for see images attach

Same experience here. The polys went right into the mounts and took up space that the OEs should have filled in to prevent the engine from sagging as the rubber aged. The idea behind the poly mount in the first place is to fairly rigidly park the engine in the OEM designed location without any added movement. When the mounts sag, headers do not fit, the fan can rub the shroud, the driveline angles can alter along with other issues.

 

[L31MaxExpress]

You can see the engine sits perfectly on the poly mount inserts. The metal tabs holding up the clamshell on the block even before the bolts go in.

You must be registered for see images attach

 

[L31MaxExpress]

One other thing I forgot to mention. The poly inserts are directional. The metal pieces are wider on the side that should be the lower side when installed. The upper piece is narrower and hits right in the factory cutout notch on the clam shells. In my 2nd picture of the poly in the metal bracket you can visably see the narrower and wider tabs. They are installed correctly as shown.

 

[eran tomer]

if your truck is 2wd i think gm mounts are still available. problem is with 4wd. you have these for 4wd.

Summit Racing SUM-7731116 Summit Racing™ Polyurethane Motor Mounts | Summit Racing

Free Shipping - Summit Racing™ Polyurethane Motor Mounts with qualifying orders of $109. Shop Motor Mounts and Inserts at Summit Racing.

www.summitracing.com

 

[L31MaxExpress]

You must be registered for see images attach

Not even close to correctly-made. Poly insert is too wide, and the steel tangs molded-into the Poly are at the wrong angle.

PS, if yours is a 4x4 just realized you had the wrong ones. Energy has them for a 4x4.

3.1152G​

The 1121s are for a 2wd.

 

[Schurkey]

At the time I bought them, both the Summit application chart, and the Energy Suspension web site said the 1121s were correct for '88 K1500 5.7L.

Summit application chart is STILL showing the 1121 as correct for both C and K, 5.0L and 5.7L, '88 to '98.

Energy Suspension 3.1121G Energy Suspension Motor Mounts/Motor Mount Inserts | Summit Racing

Free Shipping - Energy Suspension Motor Mounts/Motor Mount Inserts with qualifying orders of $109. Shop Motor Mounts and Inserts at Summit Racing.

www.summitracing.com

The Summit application for the 1152 is for Diesel and 454.

1988 CHEVROLET Energy Suspension 3.1152G Energy Suspension Motor Mounts/Motor Mount Inserts | Summit Racing

Free Shipping - Energy Suspension Motor Mounts/Motor Mount Inserts with qualifying orders of $109. Shop Motor Mounts and Inserts at Summit Racing.

www.summitracing.com

I don't doubt that the 1121s can be forced into place. They're clearly not correct in width or in the angle of the metal tabs.

 

[454cid]

I don't doubt that the 1121s can be forced into place. They're clearly not correct in width or in the angle of the metal tabs.

What are the metal tabs for?

 

[L31MaxExpress]

At the time I bought them, both the Summit application chart, and the Energy Suspension web site said the 1121s were correct for '88 K1500 5.7L.

Summit application chart is STILL showing the 1121 as correct for both C and K, 5.0L and 5.7L, '88 to '98.

Energy Suspension 3.1121G Energy Suspension Motor Mounts/Motor Mount Inserts | Summit Racing

Free Shipping - Energy Suspension Motor Mounts/Motor Mount Inserts with qualifying orders of $109. Shop Motor Mounts and Inserts at Summit Racing.

www.summitracing.com

The Summit application for the 1152 is for Diesel and 454.

1988 CHEVROLET Energy Suspension 3.1152G Energy Suspension Motor Mounts/Motor Mount Inserts | Summit Racing

Free Shipping - Energy Suspension Motor Mounts/Motor Mount Inserts with qualifying orders of $109. Shop Motor Mounts and Inserts at Summit Racing.

www.summitracing.com

I don't doubt that the 1121s can be forced into place. They're clearly not correct in width or in the angle of the metal tabs.

The 1121s are correct for my Express van and my 2wd Tahoe. The metal tab angle is also correct. You do not even have to fight the engine mount bolt hole alignment. The bolts just slide into place when you set the engine on them, even with the full weight of the engine on them. When I get to the shop next I will try to remember to take a close up picture so that you can see the tabs are exactly where they were meant to be and hold the engine mounts perfectly.