Slant Six 170 vs. 225

Before swapping engines, I'd make sure that it has had a REAL tuneup. When I got my '68 Dart, poor thing couldn't even get out of its own my. Although it ran, I was afraid to pull out into traffic. I didn't remember them being that slow/sluggish. Looking back, I can't believe how many things were wrong. Previous family had taken it to a local shop (I think it was even the local Chrysler/Plymouth dealer back in the day) to bring it back to life after sitting in a barn/garage for decades. Found them one at a time, each making just a little improvement: stuck heat riser, bad vacuum advance can, stuck distributor weights, valve lash, kickdown linkage. What made the most improvement was taking the "remanufactured" carb apart and setting the float to the correct level. Previous family had owned it since new, but I think part of the reason they let it go was it really wasn't driveable it that state of tune.