Jim, put a small block in my panel. Used the mounts from JCarter but was made by CPP and traded for a cross member. I'm running 700r4 behind the 305. As Carl mentioned the kits usually have instructions as to how far to go back, and the distance between mount holes center to center. I saved mine and can email them to you if you like.......Some places were a little close but I've had no problems and driven the panel a lot.
EDIT: Jim, I emailed you a sheet of how the mounts went in my 1/2 ton panel. May help? May not, but use as info.
can you please email this as well?
