The original cam in my PV's B18 was some sort of dreadful tractor cam. It would pull pretty well at low speeds, but quickly ran out of breath above 4000 rpm or so. Not much fun, when the cam gear fell apart I went ahead and replaced it with a D cam and it was much more enjoyable.

To build a low rpm torque monster you will need a lugging sort of cam - IPD makes a 'Street Torque' cam for automatics which should work well. A stroker cam would be a better way to add displacement for low end torque that larger pistons, but that verges into the EXPENSIVE range - remachined cranks and special rods are not cheap. It's pretty easy to bump a B20 up to 2130 cc's, though - just buy some B21 pistons and bore the block. If you have an 8-bolt crank they fir the rods, otherwise you can have a machine shop lightly ream the 6 bolt rods for an interference fit. If you don't work on the head then added displacement won't add much peak HP, but it will add power down low in the rpm range where the breathing isn't as limited.
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I'm JohnMc, and I approved this message.