Hi mate, this was a temporary thing for me as I knew I was adding turbo soon.

I just welded on a 4" pipe to the square inlet of the pizza box. Filled in the circular gaps to the square with some steel strips, welded and siliconed any pin holes as I am a hopeless welder....lol

Link here = http://www.nissanpatrol.com.au/forum...+box%26quot%3B

It worked really well actually and 100% knowing it was all sealed. I don't like the original square mount Nissan made anyway.

I was trying to find a 90 elbow 4" to 3"....Good score, wished I had of found that myself!!!!