[Justwayne]

Just curious do they have engine/trans mounts that will allow a ls1 engine to fit into a 66 ford fairlane?

 

[Yard Farmer]

Google it
Im sure its been done plenty

Might be easy, But might need more than just motor/trans mounts. Front cross member, suspension, trans tunnel, driveshaft, could be a lot of fabrication.
What you have time and money in swap, could be easier to stick with Ford engine.

 

[AdrianS]

LS has a rear sump in the oil pan so the steering linkages are going to be in the way. That'll require some significant engine setback or re-engineering the steering.

 

[64FalconFutura]

Just curious do they have engine/trans mounts that will allow a ls1 engine to fit into a 66 ford fairlane?

You could do the Fab Quest front suspension then you can put any motor in you want. Little spending but a great upgrade. I did this to my 64 Falcon and triangulated rear link and coil overs. Road and drove great!