F body LS swap mounts

78LSboo

Not-quite-so-new-guy
Aug 15, 2023
7
1
3
I bought the spohn mounts and the instructions say to mock up and drill holes in the frame. Does anyone have any pics of their f body mounts in a g body ls swap? Did you have to drill holes?
 

Built6spdMCSS

Geezer
Jun 15, 2012
5,839
9,778
113
Florida Beach
With all the sh*t out there that's direct swap in how is it this complicated. I used $33 adapter plates and got it done..

If the instructions say to drill holes I'm betting people drilled holes if they used that stuff..
 

78LSboo

Not-quite-so-new-guy
Aug 15, 2023
7
1
3
I am wanting to keep the factory truck accessories and ac. I seen a build somewhere that used the spohn mounts and cts-v pan. The compressor cleared the frame and ac box without notching. I know there is a sh*t ton of direct swap in stuff out there but most require buying relocation brackets to move the accessories around.
 

81cutlass

Comic Book Super Hero
Feb 16, 2009
4,667
13,647
113
Western MN
So you used-

The 4th gen F body block mounts
And the spohn frame mounts

Correct?

I had a local guy use this Spohn kit with the TBSS AC pump and truck accessories and it was probably the cleanest setup/method I saw on a budget. He built the car before LS swaps became a craze and the plethora of parts weren't available.
From my understanding the spohn frame mount just replaces the OEM SBC mounts (the rubber ones that bolt to the frame. If your car is a SBC, just mark the 3 of the 4 holes the mount uses and take the frame mount off (the OEM rubber GM mount for a SBC only uses 3 holes, the 4th hangs off the frame), and reuse the same holes.

If your car was a buick V6, olds 307 or something else the SBC holes are there, but have never been used. You should be able to find a picture of what holes each mount style uses and just pick the SBC ones.

You shouldn't have to drill the frame as from my understanding the bolt pattern on these spohn mounts is identical to the standard SBC frame mount used for decades across many GM chassis and all G bodies had the SBC holes there.
 
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78LSboo

Not-quite-so-new-guy
Aug 15, 2023
7
1
3
So you used-

The 4th gen F body block mounts
And the spohn frame mounts

Correct?

I had a local guy use this Spohn kit with the TBSS AC pump and truck accessories and it was probably the cleanest setup/method I saw on a budget. He built the car before LS swaps became a craze and the plethora of parts weren't available.
From my understanding the spohn frame mount just replaces the OEM SBC mounts (the rubber ones that bolt to the frame. If your car is a SBC, just mark the 3 of the 4 holes the mount uses and take the frame mount off (the OEM rubber GM mount for a SBC only uses 3 holes, the 4th hangs off the frame), and reuse the same holes.

If your car was a buick V6, olds 307 or something else the SBC holes are there, but have never been used. You should be able to find a picture of what holes each mount style uses and just pick the SBC ones.

You shouldn't have to drill the frame as from my understanding the bolt pattern on these spohn mounts is identical to the standard SBC frame mount used for decades across many GM chassis and all G bodies had the SBC holes there.
Yes sir. I have the 4th gen block mount and the spohn frame mounts. It had a SBC in it before. The bolt holes look different. I am going to dig further into it tonight.
 

78LSboo

Not-quite-so-new-guy
Aug 15, 2023
7
1
3
Yes sir. I have the 4th gen block mount and the spohn frame mounts. It had a SBC in it before. The bolt holes look different. I am going to dig further into it tonight.
I pulled the left side motor mount off today. They holes do not match up.
 

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DarrinWI

Apprentice
Jan 2, 2022
51
43
18
Madison, WI
I ditched the Sphon mounts after I received a snarky reply to an e-mailed question. I went with UMI and they fit beautifully.
 
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81cutlass

Comic Book Super Hero
Feb 16, 2009
4,667
13,647
113
Western MN
That's unfortunate that the mounts don't seem to be as clear fitting as I assumed. Maybe I need to stop recommending them? I have no personal experience using them, but one of the best swaps (fitment, complete setup with AC, cruise etc) with very off the shelf stuff I have seen used them- I have personally seen the car an liked them,

As far as I know they are the only mount that allows an OEM AC pump with pickup accessories to fit without notching the frame.

 

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