In order to fit a 1400 CVH cylinder head onto a 1600 CVH sub-assembly, you will need to make some modifications to the intake and exhaust manifolds. You will also need to use a different carburetor or fuel injection system that is compatible with the 1400 CVH cylinder head.
Here are some of the specific modifications that you will need to make:
* The intake manifold will need to be modified to match the port sizes and shapes of the 1400 CVH cylinder head.
* The exhaust manifold will need to be modified to match the port sizes and shapes of the 1400 CVH cylinder head.
* The carburetor or fuel injection system will need to be changed to one that is compatible with the 1400 CVH cylinder head.
Once you have made these modifications, you will be able to install the 1400 CVH cylinder head onto the 1600 CVH sub-assembly. This will give you a higher compression ratio and more power, but it will also require you to use a higher octane fuel.