Yeah, a 356 motor is difficult to get a lot of power out of.
I was talking with a guy with an independent Porsche repair shop at Lime Rock. He punched out a 912 motor to 78mm stroke and 91mm cylinders. I suspect that they're really 90.5mm, which yields 2007cc. Or 2029cc if they are indeed 91mm.
Either way, it's a max 2.0 liter and difficult to get 150 aircooled hp out of 2.0 liters given the head design.
It's kinda funny to me that a replica with a 2110 will spank just about any OE 356.
I got lots of dirty looks in the pits after my Spyder trounced a LOT of new P cars at Lime Rock DE(driver education). 170-180 hp and 1500 pounds. It's all about power-to-weight.