Engine charcoal and spark plug bonks

That's one blocked off heat crossover alright. Impressive
If only You knew how many 'teeners were running around that look just like that, "runs like crap when it's cold out, & doesn't want to 'kick down' off fast idle", chances are 50/50 or higher over 85K.......I've punch & chiseled bunches of intakes, then sent them to get 'boiled out' while I worked on the heads, usually timed-out good......when the parts/gaskets & clean intake came back, I had everything opened & cleaned ready for them.