You could just drill out the threaded holes in the ram stacks and then use the standard bolts.

Drill the carby holes then. Some SUs are drilled not threaded.
Or, machine the outside of the capscrews down so they clear the trumpets.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I would do that. Maybe use cap screws if bolt heads to big but should be ok.

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Options:
Fit studs to the carb and run the nut on or the reverse stud to ram etc
Drill them out and side slot so you can insert the fastner in the carb almost the full way then apply trumpet with lugs offset then rotate into position and snug up the fastener
Contact supplier and have them solve it at their cost under Australian Consumer Law
Glue and tiewire
fit them as dual exhaust tips and smile!

Drill out the stacks..you can't bolt two threaded sections together... If the standard allen bolts don't clear you can get dome or button headed allen bolts that will fit.

Cheers, Ian