Although I did not use a IFS kit I was concerned about getting the engine in the correct location so I installed the cab to help fix the location. I do not know if someone else can provide exact dimension locations but I positioned mine so I could still pull the distributor without hitting the firewall.
One method you might consider is to install the side mounts and then the bar to the block, then hoist that into the engine bay and do a location check to see where you may need to trim the crossbar to fit inside the frame rails.
Are you going to box the frame in that location? If so, you would want that done before this.
Good luck, take pictures and measurements to help the next bolter who may come down this same path.
