ECM location

[Beach Cruiser]

couple of questions for you guys. I'm running a stock LS1 engine harness on my 67 camaro LS1 swap. It looks like it's long enough to mount the ECM somewhere under the dash, it also looks like behind the inner fender would also be a good spot (where the blower motor was). Where do you guys think the best spot is? If under the dash, what's the best method to get the harness through the firewall and where to locate it?

Second question is gauges, Is there any company that makes gauges that will operate like the stock gauges off of the serial data link?

Thanks for the help