Im really intrigued by your project, LS1 in a dime sounds ridiculously fun AND challenging! kudos to you for trying to pull it off...hope you stick with it.
I honestly have not seen a 510s engine bay up close and personal for some time so my suggestions may seem a bit ignorant...forgive me for that.
after looking at those pictures posted by qwik240z it looks as though thats going to be te biggest challenge of them all..how to keep it cool. I personally hate cutting the firewalls on cars, I once sat in a datsun roadster that had a LS1 conversion and was extremely disappointed in the position of the new peddle box, there is just something about having cramped feet, or having to sit slightly crooked in a car with my legs and feet cramped off to the left to clear some stupidly large transmission tunnel that irks me greatly.
how low will the LS sit in the 510s engine bay? would it be possible to mount the radiator on top of the engine ala-WRX intercooler style? (again, In my head it sounds like it wouldn't work for a variety of reason but i felt it was worth mentioning.) what about cutting out the radiator support and making a new one out of tubing? you might be able to gain a few inches on either side and maybe even one or two up front, the headllights might get in the way so maybe a low and wide custom made radiator would do the trick. or you could just remove the inner headlights completely and leave the holes there for cooling. what about a full tube frame front end? would it be possible to mount two smaller radiators at opposing angles off to either side of the engine? 8/ maybe something like that?
anywho, what a challenge! would love to see it in person and have a go at fitting that thing in there! goodluck with it, looking forward to seeing more progress.