Not 100 % sure what it will be, BUT it won't be no 72, ( don't start it with anything bigger than a 61 If you start gearbound you'll just chase your tail) just checked lap times for Predator at there last race 400 lb was low 12 s , based on that start it with a 17/59 hoping it's still a little low on RPM, if indeed it's true STOCK don't target over 4900 RPM I'd shoot for 4850. provided were on same page dirt oval track and same track.
Good Luck !!
You'd be surprised to find how many people can't use a ruler. I got a job once because I was the only applicant that understood linear measurement. A woman once told me all women have a bad sense of measurement because men always tell them this is 10". Both true stories.