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LS swap frame side engine mounts

10914 Views 16 Replies 10 Participants Last post by  D94R
I need new engine mounts since I had to swap frames for the 07.

My swap was an RPMExtreme kit using Jon's frame side engine mounts which use the GM engine isolators.
His mounts are $299 + $31 to ship


I've PM'd Motech and JohnP to figure out who I'd get the frame mounts from now; waiting on replies.
Neither website is easy to figure out a price/availability. Also not sure if they can use the GM engine mount, or what exactly I'd have to change to use theirs.
ETA: JohnP said they have an engine mount using the JK frame side mount.


Novak makes an GEN III/IV LS engine mount that is frame side and engine isolator as one package.
Novaks price is $212 + ?? shipping.


JSS... unclear what the **** I'm looking at since I have to watch a video to see the product. I'm guessing its the engine side mount, that bolts to the factory JK frame side mount? Who knows though, no description on the site, and no technical details in the video.



Anyone else know any other options?
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Whoops, meant to put this in the swap tech area.
@j3ff3ry_j33p, can ya help me out?
Whoops, meant to put this in the swap tech area.

@j3ff3ry_j33p, can ya help me out?


there ya go, bud

I'm using Novak mounts on mine. Simple and have a of material in case you need to clearance them for the upper control arms like I did.
I talked with JohnP. Waiting for availability and pricing for engine side mounts and keep the JK frame mount.
Robbi said he'd assist if John doesn't have any available yet.


Novac is in the running then if I end up having to cut the frame mounts off.
I stumbled upon these by accident, drop in brackets with no cutting/welding.

I wouldn't use them personally as the price is ridiculous, I'd just make some with a kit from Ruffstuff or something but for a quick drop in option this should work.

https://www.bruiserconversions.com/parts/20/drop-in-ls-motor-mounts
Yah I saw theirs and laughed at the price for what they give you.

I'd make my own but the problem is making sure the 5.3 is located in the right spot. Shits tight between frame rails and firewall clearance. I'd rather pay a couple hundred for the piece of mind someone else already figured it out.
Best bet for lowest headache factor would be exact match replacement RPMExtreme. Besides, they seem like a reputable business, good customer service...

Swear if I ever have to replace the frame, I'd rather make a whole frame from scratch than deal with my kit's vendor...

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I agree. But for the work involved the Novaks would save me $~100.

Or engine-side mounts using the JK frame side mount would be the simplest.


FWIW, I did PM RPMExtreme asking some questions. He got on that night or the next day and no PM has been returned... he had been easier to get a hold of by phone though.
Ordered engine mounts from motech.

Thanks @MoTech Robbi and Wendy for the support.


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I agree. But for the work involved the Novaks would save me $~100.

Or engine-side mounts using the JK frame side mount would be the simplest.


FWIW, I did PM RPMExtreme asking some questions. He got on that night or the next day and no PM has been returned... he had been easier to get a hold of by phone though.
I haven't been getting on JKO all the much lately and for some reason my notifications were off. Email or phone is always the best.
I need new engine mounts since I had to swap frames for the 07.

My swap was an RPMExtreme kit using Jon's frame side engine mounts which use the GM engine isolators.
His mounts are $299 + $31 to ship


I've PM'd Motech and JohnP to figure out who I'd get the frame mounts from now; waiting on replies.
Neither website is easy to figure out a price/availability. Also not sure if they can use the GM engine mount, or what exactly I'd have to change to use theirs.
ETA: JohnP said they have an engine mount using the JK frame side mount.


Novak makes an GEN III/IV LS engine mount that is frame side and engine isolator as one package.
Novaks price is $212 + ?? shipping.


JSS... unclear what the **** I'm looking at since I have to watch a video to see the product. I'm guessing its the engine side mount, that bolts to the factory JK frame side mount? Who knows though, no description on the site, and no technical details in the video.



Anyone else know any other options?
Are frame mounts work with a Hemi, LS and we use the Grand Cherokee isolators that are in our BOM page.
2 year update.....

Getting back to working on this and I find I have a clearance issue with the stock 3.8 fan / stock radiator or the RPMextreme radiator / 3.8 fan and the front of the engines mechanical fan snout.

I bought the MoTech engine side mounts that utilize the JK frame side mounts. It appears the engine is now forward a bit from where it was with the RPMextreme engine mounts, but why? Unless the detail I'm missing is the MoTech mounts are designed for a kit that MUST use the Pentastar radiator fan?

And, how much more low profile is the Pentastar fan than the 3.8 fan?

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My MoTech kit came with spacers to move the 3.8 fan motor forward about half an inch.
2 year update.....

Getting back to working on this and I find I have a clearance issue with the stock 3.8 fan / stock radiator or the RPMextreme radiator / 3.8 fan and the front of the engines mechanical fan snout.

I bought the MoTech engine side mounts that utilize the JK frame side mounts. It appears the engine is now forward a bit from where it was with the RPMextreme engine mounts, but why? Unless the detail I'm missing is the MoTech mounts are designed for a kit that MUST use the Pentastar radiator fan?

And, how much more low profile is the Pentastar fan than the 3.8 fan?

View attachment 365624
My motech kit from 2.5 yrs ago was mostly ditched since I too had a build ending up like yours. No room in front of the engine right up against the fan, no room to get a 3 inch elbow air tube on, even with having shaved down the stock jk fan shroud on my 07 jk. Then on top of it I was given a radiator in my kit that had the inlet and outlet both on the passenger side. Bottom hose had to route there with a spreader tube and the top hose had to cross over the front of the engine right where the air elbow already couldn't fit!

The solution was to get the right radiator that had inlet on driver left, change the whole accessory drive to a setup that moves the water pump to the center / favoring the passenger side to allow the lower hose better access to outlet without a need for a spreader tube. Then added a one inch body lift, move the engine back a bit, pound the fire wall a bit, and when all said and done gives your engine way more clearance to the fan and radiator and your steering box way more clearance to the accessories. The accessory drive setup from motech kit had the water pump a hair distance away from the steering box which will rub under loads to the engine taking off hard from a stop. Also used the Camaro fan which saves even more space as I believe it is thinner. All the above was the idea behind a shop that helped me finish the build.

Not sure how the bruiser setup works but this picture looks very much the same as mine was and it wasn't pretty.

Good luck!
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I adjusted the whole drive train as far rearward as possible in MoTech's mounts. That bought me enough clearance that the water pump snout just touched the fan without pushing it is.

I printed up 1/2" fan spacers and that gives me about 1/8" clearance. I'm gonna try 3/4" as well.

Caveat is, that is with 1/2" spacers for the core support as well. Robbie did reply to a message from me suggesting I move the body forward on the mounts. I may end up doing that if its not a PITD. I printed the core support spacers for testing because I wasn't sure if the body was tweaked enough to be the problem (since it was wrecked) but all the body mount locations lined up just fine with the mounts on the factory-new frame... I could live with keeping the core support 1/2" forward as well if I don't want to F with shoving the body forward.
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