he’s got an n/a small displacement motor in his car, there are no turbo’s/ superchargers/ nitrous in play. the motor has stock compression/stock cams/ stock tune
this is why i said he’s not going to be in the 200 to 300 hp range so there is no reason to go bigger then a 2 1/4. not b/c when you hit 200 hp you need atleast a 2 1/4 but b/c with his setup he’s nowhere near the 200 mark to begin with
now as for a size chart, you forgot to add in if the pipes are pie cut or mandrel bent… if it’s pie cut then that totally throws off your table of non-variables