LT in 2nd Gen Fbody engine mounting location

Maybe I'm having a brain fart or maybe its a poorly made part. What did you use to mount the LT into a 2nd gen Fbody. Have a 75 frame, same 75-81. Used Dirty dingo sliding mounts with factory clam shell mounts.

Issues I am having are:
1) No pre drilled bolt hole patterns in frame line up with the clam shell mounts. Note: mounts are attached to adapter mounts on engine and lowered into frame.

2) Even with engine/ trans & mounts placed in frame & roughly positioned, drivetrain sits rather high. Perhaps a 1.5" drop would be perfect.

Visually, the legs of the adaptor mounts need to be shortened and / or tucked towards the engine more for the mounts to line up with a predrilled pattern.

I understand having to modify things when building custom cars, but when a part says 'fits said car' and its no where close, one needs to questions things.

Go to musclerods.com the have everything you need to make that swap into an F body. Motor mounts, crossmembers, headers ECT ECT

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Originally Posted by Takid455

Maybe I'm having a brain fart or maybe its a poorly made part. What did you use to mount the LT into a 2nd gen Fbody. Have a 75 frame, same 75-81. Used Dirty dingo sliding mounts with factory clam shell mounts.

Issues I am having are:
1) No pre drilled bolt hole patterns in frame line up with the clam shell mounts. Note: mounts are attached to adapter mounts on engine and lowered into frame.

2) Even with engine/ trans & mounts placed in frame & roughly positioned, drivetrain sits rather high. Perhaps a 1.5" drop would be perfect.

Visually, the legs of the adaptor mounts need to be shortened and / or tucked towards the engine more for the mounts to line up with a predrilled pattern.

I understand having to modify things when building custom cars, but when a part says 'fits said car' and its no where close, one needs to questions things.

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Are you asking about a Gen V LT?

Andrew

Since you have a Pontiac, make sure you have the Chevy mounts for a swap.

Also, Speed Engineering has some swap parts like motor mounts and exhaust.

https://speed-engineering.com/ls-con...t1-lt4-m2.html

Yes - Gen V

SE mounts are same or knock offs of ITC Billet.

In talks with dirt Dingo regarding issue. Also spoke with MR. May go with MR if DD doesn't work out.

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Originally Posted by Takid455

Yes - Gen V

SE mounts are same or knock offs of ITC Billet.

In talks with dirt Dingo regarding issue. Also spoke with MR. May go with MR if DD doesn't work out.

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I would strongly consider using Holley mounts.

Unfortunately, Holley does not make any swap mounts for the Gen V into a 2nd Gen F body platform. At least that I have found.

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Originally Posted by Takid455

Unfortunately, Holley does not make any swap mounts for the Gen V into a 2nd Gen F body platform. At least that I have found.

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If you use their LS frame stands with their LT engine mounts, it will all fit together.

Provide links please for LT swap 2nd gen specific engine mounts. They have absolutely nothing for the 2nd gens gens listed in any way for an LT swap. The frame based engine mounts are nothing more than standard OE replacements but with poly inserts. They have 1st gen stuff, but nothing for 2nd. They don't mix based on my experience. Frames are completely different. They may 'fit', but relative locations will be off.

Quote:

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Originally Posted by Takid455

Provide links please for LT swap 2nd gen specific engine mounts. They have absolutely nothing for the 2nd gens gens listed in any way for an LT swap. The frame based engine mounts are nothing more than standard OE replacements but with poly inserts. They have 1st gen stuff, but nothing for 2nd. They don't mix based on my experience. Frames are completely different. They may 'fit', but relative locations will be off.

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You would use these:
https://www.holley.com/products/engi...ts/71221004HKR

And these:
https://www.holley.com/products/engi...ts/71221014HKR

With these:
https://www.holley.com/products/engi...parts/12613HKR

Andrew

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Originally Posted by andrewb70

You would use these:
https://www.holley.com/products/engi...ts/71221004HKR

And these:
https://www.holley.com/products/engi...ts/71221014HKR

With these:
https://www.holley.com/products/engi...parts/12613HKR

Andrew

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Do LS and LT engines have the same mounting position/dimensions on the block side?

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Originally Posted by Jonathonar89

Do LS and LT engines have the same mounting position/dimensions on the block side?

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No. Those are LT specific mounts.

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Originally Posted by andrewb70

No. Those are LT specific mounts.

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It looks like the link shows LS mounts.

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Originally Posted by Jonathonar89

It looks like the link shows LS mounts.

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The frame mounts are LS, but the first two parts are LT. The engine side clam shells are designed to mimic the LS engines. It's all very clever.

Todd from Holley designed the LS swap systems for the LS. Most of the swap kits are based on Gen 4 Camaro engine mounts. For the LT he designed the engine side mounts to work like 4th Gen Camaro mounts, so any LS swap, that used to Holley swap components, could be LT swapped.

Just saw this:
https://www.crossmembers.com/product/engine-jig/

Might be worthwhile for mock up.

Andrew

The block-side engine mount hole pattern is different between the LS and LT engines. The stand-off height of the mount bosses is also different, the bosses on the LT block are 3/8" taller than those of the LS block, which means those discrepancies need to be specifically accounted for if you want an LS and an LT engine to bolt onto the same vehicle frame and have their crankshaft center lines end up at the same height with both engines.

For engine mounting set-ups that utilize the original SB Chevy clamshell mounts like you are using (AKA 2292 mounts), that means the engine side mounting brackets need to be designed to permit the clamshell to be sucked up into the sides of the LT block further than they are compared to a set of LS engine side brackets. The Hooker Blackheart 1st-gen F-body LT swap mounting brackets are an example of this type of design. Hooker Blackheart has not developed a similar set of LT mounting brackets at this point in time for 2nd-gen F-bodies.

Another method of mounting LS and LT engines is to use 4th-gen F-body type mount set-up, which attaches the clamshells to the engine instead of the frame and has the matching pedestal brackets attached to the frame of the car. I prefer and now use this type of mounting set-up in all the Hooker Blackheart LS and LT swap systems I design as it provides benefits that the old-school clamshell mounts cannot (i.e. allowing the use of a low-mount A/C compressor). We designed an LT-specific clamshell bracket for these applications that uses the same LS poly inserts and sucks them in closer to the sides of the block so that the crankshaft centerlines end up at the same installed heights in LS and LT installations, using the exact same frame side mounting brackets.

Hooker Blackheart does not offer the 4th-gen F-body type engine mount set-up for the 1st or 2nd Gen F-body applications as those systems were designed prior to the adoption of this mounting method. We currently don't offer a means by which to install an LT engine into a 2nd-gen F-body, but I would expect it will be something that gets addressed in the future.

Todd,

Thanks for the clarification. I guess I didn't have all that quite right.

Andrew

Appreciate the efforts Andrew. Had me 2nd guessing or thinking I was missing the link.

In general, I am finding a good bit of mis information on LT things in general. It is and will be improved/ correct as time goe son. Its been a good learning curve to figure things out corrected vs 'it works'.

I'm sure I'll have more questions as I dig through this.

Did you find a mount that worked for the LT swap? I'm in the same boat and was considering the muscle rods mounts.

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Originally Posted by AMPZ28

Did you find a mount that worked for the LT swap? I'm in the same boat and was considering the muscle rods mounts.

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Contact Larry at 2nd Gen Engineering (Takid455) he did finish the car a few months ago.
https://secondgenengineering.com/