I would definately put a much higher pressure cap on there, the higher pressure raises the boiling point of the water quite a bit. As to a restrictor, I wouldn't, not really needed. Just make sure you have good flow of coolant. I don't run one at all in my dragster and never have. 600 inch chevy and if I'm at 100-110 at the staging lanes before the run, I'm around 180 by the time I'm back at my pit. One of the issues with yours is the block being filled. It reduces the cooling capacity of your whole system, and it will heat up faster. The best thing you can do at this point is put in the biggest radiator you can fit in the car. You need system capacity, and the block filler just took away about half of it. Additionally, you're making more power which means more heat. The larger the cooling system, the better it's able to deal with the heat.
So my best advice is the biggest and thickest (three or four core aluminum with the 1" wide core tubes) radiator you can get, good shroud and biggest fan you can get. Put either Redline water wetter or Royal Purple Purple Ice in the system as well, it helps. Tap the manifold for four corner cooling as well, and make sure it's only water with the additive that you're running, no antifreeze!!!! Besides being horrible to clean up if spilled, it actually doesn't cool as well as straight water.