360 to a 408 how much quicker

I think it's the 48 extra cubic inches.
Sorry, I shouldn't have been sarcastic. But, you will always have the extra inches, no matter how much the 360 or 408 is scienced out.
Also, just for those that may not be aware, NHRA and IHRA Stock Eliminator have different rules than IHRA Crate Motor. "Stock" intakes and stock lift w/ any duration cams in Stock. "Stock" heads in Stockers, too. I was a NHRA Stock Elim racer for a while, I'm not familiar w/ Crate rules. Maybe Myron can fill us in some.