My b20e, k cam, k jet has always pinged badly with timing set to specs,[am using premium unleaded]. So tried B20 Pauls advice and closed inlet clearances, am running .012" inlet, .016" exhaust. Static timing is 10 btdc, total runs to 34 btdc, also fitted vacuum delay valve off some jap car i had laying about to vac advance diaphram. The difference is quite amazing, no ping at all and running right timing have a lot more power. As Paul says the extra overlap dumps some compression but lets it breathe better, someone posted that Volvos specs were one size fits all for convenience in service depts, how right he was.Thanks Paul for sharing your hard won knowledge. Jack.