it was a circle coupler that stretched a little to fit the aluminum tube leading to the throttle body. It did have to stretch a little... if i was going to do it over again i would use 3.5" throughout- couplers, aluminum tubing and all.

Further down the road i may experiment with fabricating an enclosure for a conical filter-
I would definitely want to buy another mass air meter housing to cut up rather than using my mina gallery housing which is smaller in diameter. But, that will be a while away.

 

Coming soon....... More details to follow..