You didn't mention bore,stroke or cubic inch restrictions. Rods have to be stock,but do they have to be chevy? Olds has a nice 6 inch rod,gm part no. on it! They check port inlet/outlet only? You can make quite a bit of power just cleaning up the bowl. Make a carb spacer out of hardwood,doesn't tranfer heat.Remember what I told you about engine placement,makes a huge difference in handling. Hank