Are there any easy add ons to make more torque on a 170?

A high-ratio rear-end would be the easiest way to get an assured torque increase. I think there was a ~3.3:1 gear set. However, that would hurt you at highway speeds in mileage and the engine sounding like it is trying too hard. Also, consider down the road if you might change to BBP for front disk brakes.

The 1 bbl should be fine for torque, just not high air flow (max HP). Same deal for your stock exhaust. You might do better with electronic fuel injection, but not easy since no store-bought solution. It would improve mileage though.

The cheapest approach that might help would be electronic ignition. One cheap way is a stock electronic distributor (72+ engine) and the 8-pin HEI module/coil from a 85-95 GM V-8 truck. That is what I did on my slant. A Pertronix ignitor or Crane Cams XR700 would fit in your existing points distributor, so easy, but only cheap if you buy used on ebay. Get ignitor II to lose the ballast and run hotter. I wouldn't fool with the more complicated Mopar electronic ignition.

If you do install a 225 engine, if a later one (~67+), get the $20 ring to adapt your torque converter snout to the larger crankshaft bore. If not, you will be bad vibrations and possible destruction.