Usable with harder and double valve springs…. by high firmness is ensured, which these bars do not become bent during load. They are supplied with loose heads and are about 10mm shortenable. Been suitable for type 1 engines with 40/44+50PS WBX and type 4 engines….Not suitably for 34 HP engine with 1200ccm… Quotation 1 set of 8 pieces