Careful with that late model intake. Looks like maybe a mismatch with the heat cross-over.
Yeah I noticed that right off the bat. It was a '77 numbers matching W72 400 motor. The heat riser matches the intake port and that is dead space. After much research and pondering I decided to not fill or block it off as the benefits are short lived, the heat still soaks through the intake after 20 minutes or so. You might shave a tenth off of your 1/4 mile but two runs in it'll be back up to the temp without block off plates.
After years of building Chevy motors, these Poncho nuances are really keeping me engaged and learning.