Inliners International Forums General Discussion Engines Need to know exhaust pipe diameter for GMC 302.

What vehicle is your 302 in?

A stock 302 in good tune will make about 160 HP and signs off at about 3400 RPM. Adding a set of Nicson headers and dual carbs will make a big difference. The factory cam is all torque and economy, but the valve and port sizes are very generous so a performance cam will really transform a Jimmy.