can you post a pic of the engine? as long as there is still a fairly straight path and you use an adequate size tube, you should be fine doing that.
http://www.gassavers.org/garage/view/1372
if you look at my pics, I could have possibly put the hole in my airbox further back and routed it to the back of the engine if it were set up like yours (I am assuming a lot with that statement). I personally am seeing intake temps between 130 and 150 (I may have said that already). I could easily get them higher with a better heat shield. I chose not to because I have seen temps approaching 180 (my highest so far has been 179) and I don't feel comfortable with temps any higher than that.
also, think about this. if you have a heat source and you blow a fan across it, the heat source has to be significantly hotter than the expected air temperature that you are hoping to get.
I think you will get hotter temps with your setup but the question is how much hotter. I just don't want you to go through a lot of trouble to see 20 degrees above ambient temp. that would be disappointing. I personally don't like doing things twice. there again, you do have a delema with the header location.
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