Indy heads single water crossover /single plane manifold.

Couple of questions:
What are you running for ignition, and what is your timing set at? And total advance @ what rpm while we're at it... Timing has a surprising effect on operating temp.
What is the hidden 2-belt accessory being driven underneath the alternator? A/C? Supercharger?
And for what it's worth, every smallblock manifold I have ever seen is a single crossover.