I think your estimate is good. It could make a little more too.

Do your SR heads have the 2.25" intake valves?
Do you know the final intake port volume after porting?
Is the block bored to 4.500" ? That can help breathing compared to a 4.375" bore, etc.
What size headers? Dyno shop headers or car headers?

1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1