Outer Limits 4x4 Board

I have started an airbox conversion on my 97 Hilux 2.8 diesel tray. I have removed the original airbox in favour of a Surf airbox to give me enough room for a second battery at the front of the engine bay (passenger side). I have come across a major problem.

The outlet on the surf airbox is approx 56mm and the diameter of the inlet on the intake manifold is approx 70mm. I can't find a flexible, heat resistant hose that will accomodate the difference in diameters.

My idea for a sollution is: to have a exhaust place fabricate a piece of pipe that reduces from 70mm to 56mm with the appropriate bends and curves in it then it can be joined at either end by a short piece of silicone type hose (the stuff used on turbos and intercoolers). Will this work?

Does anyone have any other ideas for a sollution. This is the last obstacle to complete the project.

Mate i used a peice of flexy hose i picked up from a truck spares place and another rubber peice (like radiator hose) under it on the small end to increase the diameter so the flexi could clamp down nicely

intercooler joins have those sizes check ebay