Picked up a 64 Valiant
360 is in the Dart. That one will get me there fast with tickets in hand.
The Valiant will get a warmed over 225 (short block is already built in the garage) once I get the head milled .040 and talk myself in taking apart a running car that I have been waiting a year to use!
I might build the 170 as well, I kinda' like the idea of the motor: short stroke, high rpm 6.
The worst sludge I have seen was a 4.0 Jeep Cherokee. I was having "blow-by" issues: oil in the crank breathing system to the point of it leaving a puddle in the air cleaner housing. Pulled the valve cover and it looked like it still had a valve cover on it. Quite a clean up that time. Used steel rods to clear oil drain backs and used diesel to dissolve the crud. Ran great after that.