Is valve shrouding a concern in a 318 w/ 2.02 & 1.6 valves

Why not start with a 360 block, an aftermarket crank will be required for the hp anyways... offset grind the crank and destroke the crank running small block Chevy rod journal size your going to need to run an aftermarket rod too... and might as well get the lighter parts.. This way you can get you to the cubic inch you want with an over bore to 360 +/- 1% Much better piston and ring availability and hp potential. Good luck it sounds like an uphill battle.