Hi Angelo,
Congrats on the purchase of your kit. There are other RCM's on this forum as well as others that I'm sure you will get to meet over the course of your build. Really helpful blokes too.
Choice of engine re Ford, GM or other is entirely up to you. I didn't go to the Nats this year but I was told that there were a few Ford SOHC 5.4s as well as DOHCs as well. LS1's would probably now be non complient so you've only got LS2's to choose from. Any Toyota model would have to be from a late motor (In VIC), not 1/2 cut import which usually makes them too expensive. So there are a few choices available to you. Generally speaking, when your car gets it's VIN you go back three years for the applicable engine emission rules. Problem is the rules keep changing so you have to be very carefull that you don't get caught out. Speak to your engineer first before you buy anything and buy your engine late in the build, not at the start of the build. I'd suggest to talk to RCM's preferred engineer to get a detailed explaination.
Cheers and happy building
