[Dave at Pelican Parts]

If I recall correctly, GT-3 requires stock dimensions for bore and stroke.

The answer, in a nutshell, is "TONS of money!" Big springs, very definitely. Everything balanced to within an inch of its life, most certainly. Lightweight reciprocating and rotating parts wherever allowed by the rules.

Lots of cam, lots of carbs (as much as allowed by the rules), lots of head-work, and a well-designed exhaust. Without that, there is no point to going over the stock redline, as power has fallen off to the point of absurdity by 6000 RPM.

--DD