Are you looking to inspect your intake valves:
a) to look for a burnt area on the valve seat?
b) to look for carbon buildup between the valve stem and face?
If it’s the former, then a leakdown test would work fine.
It it’s the latter, then a borescope-type device would be better.
Could you remove the spark plugs and go in through the plug opening, and look at each valve when it’s open, by manually rotating the engine?