how hard to replace small block with big block in 73 charger

[texas charger 73]

My charger is a 318/904 combo. How hard is it to convert to a 400 or 440 with 727? My 318,sounds beefy but it might have barely 250 HP. I want to go big block but its not like cheverolet where everything interchanges. I have hears from some you have to change the whole k member and I have hears from others they make universal mounts now! What would be needed besides motor and tranny obviously.  New harness? Different radiator? Bigger springs? I know people have done this before with much success.

[RallyeMike]

I'd suggest a quick search on the site. It has been covered more than once and there is a ton of discussion on the subject.

You don't have to change the K if you use Schumacher monts. You don't need a new wiring harness if you just extent the distributor and coil wires to reach the front of the engine. You will need a bigger radiator with the inlet/outlets in the correct position. Larger torsion bars are recommended, but not absolutely required.