[thecerealcommie]

Efficient ignition is another area to consider... I'm assuming the distributor isn't stock or at least has a set of optical points. An ignition box like the MSD 6A and a good coil, in conjunction with a good set of 8mm wires and new plugs, and you'll be getting all your spark there with minimal loss of potential power.

Do you have a high flow air filter? This is a particularly cheap power gainer.

You mentioned that all the vacuum hoses had been cut to take the motor out, are you sure you don't have any leaks? A vacuum leak into the manifold or carb is a big no-no and robs power.

Hope this helps