that's exactly it, since your engine is a side exhaust, a rear exhaust header will be perfect my friend
, let jay show you the way, by the way my name is jay
. Ok, the way your engine would sit in the r40, the exhaust port would be facing towards the rear of the car, in the r40, in a rear exhaust engine, the exhaust port faces the towards the right side of the car, so in your situation, it will face towards the rear, in that case, a rear exhaust header is what you need, let me give you a link to some rear exhaust headers
http://www2.towerhobbies.com/cgi-bin...?&I=LXXH37&P=0
http://www2.towerhobbies.com/cgi-bin...?&I=LXAMZ5&P=0
http://www2.towerhobbies.com/cgi-bin...?&I=LXCPR9&P=0
not sure if these will fit, but you'll need something of the same style, hope this helps