My friend has bought a cuore 2004 with 126K on odo. it goes to speed of 100 on petrol and 80 on CNG. our mechanic told us that its head is swapped with kabuli 660cc cuore, engine is in overall good condition but it will not get high speed. its tyres are 165/70 R12. i want to ask experts that is the mechanic right? Is there anything we can do to make it reach 120, a reasonable highway speed. also what is the cost of genuine or kabuli 850cc head of cuore?