So I have some technical questions for those master mechanics out there. I understand a great deal of how internal combustion engines work and know most of the facts about the PCM 409 and 450 engines. My question is a bit more in depth though as I seek to understand the difference in these two engines better. WHat is the actual different in them. I have been told that the 450 is just the 409 on a tune. If that is true, is it just a ECM tuner that have on it or is there actual mechanical differences. Is the VVT change in the 450 and are different injectors used? What are the actual differences in the 2 engines and whats to stop someone from turning a 409 into a 450 if its just tuning? Also for both engines with them having high compression ratios(but not force injection) would it be better to run higher octane to avoid predetination vs the recommended base 87?