I had a pentium 3 in a g3 powermac case. If I recall the whole io area just unscrewed, then you just had to mount standoffs and use a cpu cooler that fit under

I had a pentium 3 in a g3 powermac case. If I recall the whole io area just unscrewed, then you just had to mount standoffs and use a cpu cooler that fit under the psu. Today, with a 3d printer, the mod could be done very elegantly.