Even every low mileage engine i have taken apart has alot of carbon build up like that . The only thing you need to worry about is the wear ring around the top (after you clean the caarbon back). If you plann on changing the stroke you need to make sure there isnt a lip there or it will break a ring . If you stayed with stock stuff this wouldnt matter because the rings would never go past that point .

Looks good let me know if you need anything . If someone has a h part for sale odds are i know about it.