That cap is the functioning one connected to a generic expansion tank. The front rad. cap is plugged and only for burping/filling.
I used 1" x 1.25" silicone elbows on the engine, and a 1.25" to 1.5" coupling from the cross tube to the tee. The tee and header tank 1.5", and the AL 45 is 1.25 into the header tank.
Yes, the 2 ports that feed the heater and TB are tee'd together and connect into the header tank. They should make good bubble routes to the cap- all uphill.
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