Advanced Engineering Tech - clearance issue?

if i build a 408 with a 4.030 bore and run L92 heads will i have clearance issues with the valves to block? will i have to do any valve shrouding any tips for those who have done this setup let me know

You will be fine. Obviously a larger bore is better with the spread on those valves but it will work ok. In my opinion the valve shrouding thing is overblown with respect to the larger valves...you still get the curtain area. Even smaller valves are up against the cylinder walls.