gmc exhaust question

[Vic Eaton]

HELLO TO ALL
Anyone fitted a gmc exhaust my question is which side of the collar thats the part that holds exhaust to manifold does the gasket go the hole in the gasket i have is not large enough to go over the exhaust tube and stops the collar from bolting up tight so does it go on the exhaust befor the collar even that looks strange to me need to get the old girl ready for rememberance sunday so time is running out . would be glad of advice.
vic eaton uk.