Lockup 904 question

the 904 LU is not built for power-handling; it is strictly a fuel-economy feature.
It gets its apply signal from the line pressure and it's cut-out signal from the combination of line pressure plus TV pressure; so it's the first thing out when you hit the gas.
Could you make it manual?
Sure, but I can't imagine why you would want to.
Plus the stock combination works pretty slick.