4.00 stroke, 6" rod, 1.20 compression height piston.
This is the answer to your heading of the topic.
But the answer to your question inside the thread is a tough one. The longer rod is good, at the expense of a shorter piston. I don't really go for all the "rod ratio" crap, so i just jammed in all the cubes i could get inside a 9.2 block.
2 years on, and the 4" stroke jobbie is running like a dream.