per google conversions are

lb/hour to g/s x*0.125997881

g/s to lb/hour x*7.93664144


24lb/hr*0.125997881=3.02394 grams/s
42lb/hr*0.125997881=5.29190 grams/s

Lets take or example 50ms BPW and convert it for 383ci @42lb/hr
50ms[x/1000=0.05second]*3.02394=0.151197 grams of fuel

so 50ms BPW delivers 0.151197 grams of fuel at 24 lb/hour injectors.

346 ci to 383 ci is 10.7% difference.
Hope the 383 ci is correctly calculated and not marketing cubes like 350 is.

0.151197 grams * 10.7% = 0.1673751 grams needed or the new displacement.

SO for 383ci you need 0.1673751 grams /3.02394 =0.05535second BPw[55.35ms] at 24 lb/hr

or 0.1673751 grams /5.29190 =0.03162seconds BPW[31.62ms] at 42 lb/hr.

I doubt the cam will be a factor here since cammed only lt1 fires straight up with stock tables.