Well this is one hilarious thread..
Lucky our friend Mr Shelby finished up at Ford and had a life long relationship there..
Aussie cars that intend to be street registered need to meet the emissions codes specified in the ICV regs, which equate roughly to the 2000 ADR standards. So cats are required and the total vehicle noise on a drive by at around 3700 rpm must not exceed 90dB. The engines must also be an AU designated unit.. ie, for an approved Aussie street vehicle, that has passed a relevant emissions standard or the RTA simply wont recognise it.
That said the 5.4L Falcon motor sold here (prior to the 5.0L coyote) is a very difficult engine to get past emissions, is apparently fairly dirty. The 5.0L is a big motor, with dual OH cams, but is possible in an FFR kit at least, although I've not seen the mods to the engine bay in detail..
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If you are building a track car.. then go for broke with a small block full house crate motor from the US with stack injection and a matched cam..
I know I would..
I have an LS3 for my FFR Coupe and would love to be able to fit a set of alloy covers to it (my turn for a very naive question now.. !!). Was the comment re an FE valve cover comment for real..?
Cheers
Chris