I doing a complete remodel of interior. I can't figure out how to remove furnace from cabinet. I removed the grills interior and exterior. All the screws around unit both inside and out. disconnected gas line. Still solid. Don't see any other attachment screws to remove. Any suggestions would be appreciated.

I successfully removed furnace! Just needed a little encouragement from a block of wood and a hammer. After 37 years the vent and furnace had fused together. Like they say, when all else fails, get a bigger hammer.