Stop in for a cup of coffee

You may need to notch the cylinders for the larger 360 valves in a 273....
Yes, I'm aware of this. The cam I've ordered (this Lunati cam, 235/243 @0.050", 110 LSA, 525/546 lift) will probably require machined valve guide bosses and valve pockets too.
The 360 heads I'm getting has offset retainers so that might take care of the valve spring pockets but I don't know what springs are in them, I'll need to research that.
I do have the correct springs for the cam as well as NOS Lunati solid lifters from 2012.