Been seeing some prodrives with a "Stage 3 70HP" upgrade kit and I've poked around a bit on the internet and can't seem to find one! Any info and opinions on them? Is there a kit you can buy that's basically a "bolt-on" deal or is it more of a machining process? Preciate the input!

when yo get to a stage 3, your talking about building the whole motor from the bottom end all the way to the carb. Lots of things go into a socalled stage 3 build. cam, rods pistons valves heads intake etc.

Stage 3 requires the engine cylinders to be bored and/or re-sleeved.

It's not something you want unless you're mechanically inclined, as it can become quite pricey.