4 Inch Turbo Bell to 3 Inch MAF Pipe
I did this last night when I added a Turbonetics 60 Series Turbo with a 60-1 / P Trim Turbine onto my GNX
I also used a 4 inch to 3 inch bell adapter and when installed, the clamp (for the adapter to the 3 inch MAF pipe) was just touching the wires on the stock location IAC
Not hard enough to rub thru but close enough that I will probably put some friction material in between the clamp and the IAC wires
Good luck
Ray