Tip for Ca. front cat.

I just replace the front cat convt. in my 98 metro. It's part of the exhaust manifold. Had to order it from Dealer. $550. When it came it was in parts. The cat material , a fiber wrap and the outside housing. You have to press it all together your self, very dangerous. Tight fit. I forced it 2/3ed of the way in. Tried to tap it with a hammer but pieces were chipping off. Finally got one of those pipe clamps that use an iron water pipe so it will go out 36 inches. Put the piece on a flat bench or counter edge. Hook the clamp under slowly crank it in.