To answer the original question.
The deck height is 10.2 inches instead of 9.8 to compensate for an extra piston ring, the crank and rods on the 427T are the same as a 427, the crank is the same stroke on a 427t as a 396 and 427 but the second counterweightis a little larger. The heads are interchangeable but the intakes on the 366T and 427T are wider to compensate for the extra height. THE ONLY DIFFERENCE IN PRICE IS IF YOU ARE CHANGING INTAKES. and that difference is the cost of the spacer kit you will need to adapt a standard 9.8 deck intake. If you are replacing anything else the costs will be comparable to building a standard deck BBC.
The 366 is pretty much only good for low end torque, the small bores cannot be made much larger. IF you have a 427T like stated above you can get big power out of it, but not any more than if you had a standard deck block unless you go with an expensive exotic rod and piston combination.
Good aftermarket pistons are available for stock type rebuilds at comparable prices. A decent set of 049 head castings are available and will be more than enough flow for a stock type rebuild.
The only aftermarket intakes available for tall deck motors are for high RPM race use and would not work well, but a dual plane RPM intake and some spacers will really wake it up.
How do I know this? I have built several in stock trim and stroked to 496 they are all quality motors but Big Blocks are naturally more expensive. Do your research and you can find an affordable, powerful combo that will put a smile on your face when you step on the loud pedal.