Your comment reminded me of an "issue" I ran into with the cooling fan. I believe the stock fan in my '68 Firebird 400ci is supposed to be a 19.5" fan. A previous owner installed an 18" fan w/o a fan clutch (probably to improve cooling...which I also have been chasing). I decided to put a 19.5" fan back in to see if it improved cooling but noted it will not fit in the shroud w/o rubbing. The shroud opening is big enough, but for some reason the fan is not centered in the shroud....and I wondered if someone had installed the engine off center. I was able to move the radiator and shroud over about 1/2, but that still did not provide enough space. I have been trying to figure out what I am missing.