I used 2x2" air conditioner sealing foam from the local hardware to seal mine but Moroso has a foam kit that I believe is 1 3/4" thick by about 4" wide and maybe 2-3' long you can buy and trim to fit
416 stroker from Nick at Compu-flow. 11.14 in full street trim. Seems like a new best every time out. 11.06 open headers----so far!!
