[Dave at Pelican Parts]

Spacers will put the heads 1/2" farther away from the block. You'll start running into issues when you put the engine tin on, when you put the motor in the car, when you put the pushrods and pushrod tubes in... And so on.

Those are a lot of issues to solve for your $300 "savings".

Check into some 96mm pistons and cylinders. You'll get more displacement (2055cc) and they are often cheaper than the 94mm ones.

--DD