The Z bonnet is unchanged throughout the run from 1969 to 1978. The only difference would be on 280Z models (non-UK) which had a pair of raised cooling vents either side of the bulge to the rear. Even these bonnets drop straight onto a 240Z or a 260Z and have an identical bonnet bulge. Quite a few UK cars ended up with these foreign bonnets due to an oversight by one of the pattern parts suppliers when placing an order for new stock.....oops! The vents are now no longer available, even as a new USA import part.