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LS3/LSX swap - engine mounts

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Old 08-23-2018, 05:58 PM
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corvettedave383
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Default LS3/LSX swap - engine mounts/driveline angles

LS3/LSX swap - engine mounts

so ive seen that great post on here, where everybody writes down the parts they have used to swap, but it doesnt really talk in detail about these parts used

so iam looking for engine mounts for my LSX B15 installing it into my 78 corvette with tremec t-56 gearbox, so which mounts kept the engine in its stock position, aiming to use poly bushed mounts, whats my optiins out there and what works best in peoples thoughts?

thanks for any help

Last edited by corvettedave383; 10-09-2018 at 01:51 PM.
Old 08-23-2018, 10:49 PM
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Originally Posted by corvettedave383
LS3/LSX swap - engine mounts

so ive seen that great post on here, where everybody writes down the parts they have used to swap, but it doesnt really talk in detail about these parts used

so iam looking for engine mounts for my LSX B15 installing it into my 78 corvette with tremec t-56 gearbox, so which mounts kept the engine in its stock position, aiming to use poly bushed mounts, whats my optiins out there and what works best in peoples thoughts?

thanks for any help
CIC has some nice mounts and are dual position which is stock or forward. I'm running them on my ls3 swap and made life easy.
Old 08-24-2018, 06:18 PM
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ignatz
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What do you expect to do about your clutch? I would have to dig through some receipts to figure out what I put together some time ago

Old 08-24-2018, 06:25 PM
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no worrys with clutch, i have a hydraulic clutch release bearing, what mount is that in your pic?
Old 08-25-2018, 01:57 PM
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some mounts i was thinking either

http://www.vetteworksonline.net/cata...php?cPath=9_69 or https://www.corvettemods.com/C3-Corv...t_p_18395.html

anyone use either and thoughts?
Old 08-25-2018, 04:24 PM
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Originally Posted by corvettedave383
I tried to use the mounts in the second link with an LS3 but they located the engine too high and forward. I love the mounts they are clean looking and do not look like adapters. I still may modify them to work, not sure yet.

Old 08-25-2018, 04:46 PM
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Originally Posted by JVetthead
I tried to use the mounts in the second link with an LS3 but they located the engine too high and forward. I love the mounts they are clean looking and do not look like adapters. I still may modify them to work, not sure yet.
Are those poly pushing with some compliance? I am not a fan of solid mounts on an aluminum block despite all the people who say no problem. My motor already sits too high but I have to wonder if it got lower that I might have another set of clearance problems to be solved.
Old 08-25-2018, 05:10 PM
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Originally Posted by ignatz
Are those poly pushing with some compliance? I am not a fan of solid mounts on an aluminum block despite all the people who say no problem. My motor already sits too high but I have to wonder if it got lower that I might have another set of clearance problems to be solved.
Yes they are poly bushed. I had to get engine further back for 5 speed shifter to be located in proper position, that was the problem for me. Yep oilpan is very low.
here are the adapter plates on now

Old 08-25-2018, 05:15 PM
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ahh thanks great info, so what brand of adapter plates are you using?
Old 08-25-2018, 05:24 PM
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Originally Posted by corvettedave383
ahh thanks great info, so what brand of adapter plates are you using?
Afraid that would be asked, I don't recall... They are nice thick aluminum with 3 fwd/aft positions.

Found it.. crap, link wont post
SR adjustable on ebay

Last edited by JVetthead; 08-25-2018 at 05:29 PM.
Old 08-25-2018, 05:55 PM
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https://www.ebay.co.uk/itm/CHEVROLET...oAAOSwZjNba8Zx

these ones?

and your happy that engine is at same height as before, so no playing with propshaft angles?

Last edited by corvettedave383; 08-25-2018 at 06:00 PM.
Old 08-25-2018, 07:47 PM
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Originally Posted by corvettedave383
https://www.ebay.co.uk/itm/CHEVROLET...oAAOSwZjNba8Zx

these ones?

and your happy that engine is at same height as before, so no playing with propshaft angles?
Looks like the one. I have not checked angles yet
Old 09-05-2018, 06:43 PM
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for the guys that used the energy suspension poly style engine mounts, did you still use the backing plate? i get a feeling its not required because the lsx conversion plate acts as a backing plate?





anyone?
Old 09-05-2018, 09:56 PM
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Interesting question but I couldn't remember so I had to go out and look at my car. It is there, best I can tell and I think it was fitment issue with getting the original mounting bolt to line up. Without it the center to center distance to those mounting bolts becomes quite a bit smaller. It does of course make the motor sit even higher which was problem for me. This was five years ago just so you know. I posted a picture for you of the driver's side, here is the passenger's side. I guess you'll know when you try to drop the motor in what you need. Of course that becomes very awkward at that time. Looks to me like you will want it!

Best
Cliff



Last edited by ignatz; 09-05-2018 at 09:58 PM.
Old 09-06-2018, 12:27 PM
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Thanks for your pic an reply, what does this backing plate actually do? would the lsx conversion plate mounted to engine do the same job as the backing plate?
Old 09-06-2018, 01:29 PM
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I ended up using the LSX innovations plates that move the engine forward 1". I originally tried the 3 position ones they offer (stock, 7/16, 1.75, 2.25), but it didn't work for me. I think the reason I ended up with the 1" was then I could use a stock c4 auto driveshaft. From what I remember too, I wanted to go forward to make sure the tranny cleared the tranny tunnel (that fit check will be coming in the next month or two for me with any luck).
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Old 09-06-2018, 01:50 PM
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Originally Posted by corvettedave383
Thanks for your pic an reply, what does this backing plate actually do? would the lsx conversion plate mounted to engine do the same job as the backing plate?
As mentioned, this is from five years ago. Let me repeat myself. "Without it the center to center distance to those mounting bolts becomes quite a bit smaller." I am suggesting that if you drop the motor in without these plates, the center-to-center distance between the mount holes would not match the center-to-center distance between the frame holes. From the picture it does not look like the mounts could move up on the slant to accommodate the chang in distance between the two.

This fits and everything works, any experimenting with and without is up to you! I cannot comment on alternatives.

Last edited by ignatz; 09-06-2018 at 01:52 PM.
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Old 09-06-2018, 04:13 PM
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Originally Posted by ignatz
As mentioned, this is from five years ago. Let me repeat myself. "Without it the center to center distance to those mounting bolts becomes quite a bit smaller." I am suggesting that if you drop the motor in without these plates, the center-to-center distance between the mount holes would not match the center-to-center distance between the frame holes. From the picture it does not look like the mounts could move up on the slant to accommodate the chang in distance between the two.

This fits and everything works, any experimenting with and without is up to you! I cannot comment on alternatives.
Thanks Cliff, thats better your speaking in english now, so we can all understand now
Old 09-12-2018, 06:49 PM
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Anyone else done the LS swap got any thoughts on motor motors and backing plates?
Old 09-16-2018, 02:18 PM
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Thats the engine in, looks ok for position , need to get gearbox in next see how that all looks






Last edited by corvettedave383; 09-16-2018 at 02:22 PM.


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