Volvo Repair: 4cyl hesitation, vacuum leaks, demolition derby

Question
I just bought an 84 244 at auction for the 4 cyl demolition derby at my county fair, always heard volvos were strong. It will often spit back if you mash it off idle, and miss run terrible until about 2500 rpm 4 to 5000 its smooth all the way up to the rev limiter,also get a big spark knock when you mash it off idle, What should i look at ? also do they have a safety switch that i need to bypass before running it in a derby?

Answer
Sounds like a good place to start would be to set engine to specs...base idle,timing,co...check for vacuum leaks and make sure your distributor cap and wires are in decent shape. Clear spray paint will help against moisture. You may have a bad air mass meter...check that timing first though