Please check your posting to see if there were any typing errors.
I have checked a number of resources and not found anything close to the intake casting number you posted.
All of the Chevy intake casting numbers I seen, have either 6, 7 or 8 digits before a letter, if present.
I have not found any intake casting numbers with 5 digits and a letter as posted.
I'm hopeful there may have been a typing error in the casting number in your post.
If not, it's a real interesting intake!