I checked out the Turner website. they recon the heads are 8:1 comp ratio and gas flowed. The testimonials look impressive, think Ill start another thread about turner heads see what the good folks online reecon. Apart from having a soft spot for petrol series Landys, going for a petrol with lpg is bound to be cheaper for insurance as it represents less of a conversion than a 200tdi or an Isuzu Daihatsu Toyota etc conv.