short answer no, long answer yes.
although the b18c(1) and the b18(a/b(1)) are 1.8 liter engines they have a few differences while having one likeness.
when the engines start out with initial casting they are the same, they even share the same casting number, while being physically taller than a b16 all b18 engines are the same size and bore.
once the engines go for machining is where it all changes, the vtec engines are drilled with a few extra bits to give both a vtec oil passage and oil squiters that spray the underside of the pistons.
they also recieve an extra hole on the back of the block to accept a knock sensor.
the internals of the engines are very different as well, the ls engines (b18a and b18b) are identical, while the gsr engine uses a different crankshaft, rods and pistons, as does the type r engine use yet another different set of rods and pistons, as well as a different crankshaft.
depending on what you can get your hands on you can do a few different things with an LS block.
a poor mans type R can be had by using your LS block, LS crank and rods and use b16 pistons, this bumps the compression and lowers the weight of the rotating assembly (some) use your choice of vtec head and run the appropriate vtec oil line.
you can also transplant the internals of a gsr engine to an LS block (crank/rods/pistons) this will yield a shorter stroke and bump up the compression.
Alot can be done with an LS block if that is all you can afford, almost any combination of b series parts can be used to make a streetable or even competitive LS/vtec engine.
see the swap and refrence sections of this forum to see what else can be done. and if you have an idea but don't know what to do then just ask, someone will gladly help.