swaping a 400 engine into an LS info needed
 

Disclamer: New member and a complete noob when it comes to this car.

My cousin recently purchased a Mote Carlo LS, the motor was in so so condition so we decided we should should swap it for a built 400 he had laying around from his 72 Impala. What motor mounts would we need to drop this in? Would the mounts from an SS work ?

Also we have a 700R transmission would we need a custom drive shaft due to length of transmission or can we source one from another vehicle.

The engine we are putting in is a carburated engine and will not be converting to fuel injection. Would we have any issue with the ECU other than a check engine light due to the lack of sensors we wont be using ? Any way to just get rid of the check engine lights?

How many more issues would we encounter doing this swap any info on this would be greatly appreciated.