QUOTE (rdaharry @ Jul 7, 2009 - 12:59 PM)
I have looked them up on ebay for both the 1.6 & 1.8 and the only difference I can see is the o2 sensor hole, bolt pattern looks the same, but not sure if the length is any different. I also read something somewhere that the only difference between the 4afe & 7afe is the block, that's how we go from 1.6 to 1.8. and the 4 and 7 only means that they are different generations, ie: 4th & 7th generation. I don't know how true this is, reason why i'm posting the question.
I'm not sure how true that is either (I just genuinely don't know the answer) but I've also seen on eBay that almost every 7AFE header on there is advertised for a 4AFE as well. I think though that you are correct about the blocks being different and the heads being the same, in fact, I'm almost positive.
http://www.toyoland.com/engines/4A-F.html