You can refill coolant by removing a threaded plug on the head on the intake side near the rear. (that rhymes
That is what I believe I read in the service manual yesterday.
I wondered what that plug was under the exhaust manifold when I had my engine out the other week. I should have removed it and anti-siezed the threads when I had the chance while the block was on the stand.
Still waiting for the darned chain crimp tool!