Questions on turning a B16a into a B18c5.

I already have the pistons, so what else do I need? Is the B16a head the same as the B18c5? What type of compression am I looking at?

u notice u are .2L less displacement right?
you will have way less c/r too because of this too.
if you want to make ur b16 quick go with aftermarket pistons or b17 crank and rods with 1 layer headgasket.

the piston dome displacement of the b16a pistons are actually just slighty larger than the b18c5 pistons.
so if you plan on using the b18c5 pistons in ur b16a, you will have a slight loss in compression.
what you need is the entire block from either a b18c1 or b18c5. theyre both the same with different internals, since you already have the pistons the b18c1 from a GS-R integra would be easier and cheaper to source.
Its true that the b16a head is the same as the b18c5 head. except for having a different valve train, a port and polish job and milder cams. so you’d also need that.

get a stroker kit…you’ll get forged pistons and rods with the package. youll either match or exceed the b18c5. youll probably have to do some machine work or resleeve in order to exceed displacement. you might be able to get a ITR crank as well, and then itr rods.

Another option is running your LS crank and rods and upgrading to Tech43 pistons…you might have to bore your block a little but ut comes out to 1.9 with the rod stroke ratio of an LS.