helo dear ,
this may be good but i never tried it , and i want to tell you what i have tried and tested on mehran , mehran stayed in my use for almost 5 years and i overhaul its engine once on my own , and i do some modification in it , just want to share here with you ,
first of all i do porting on its head , mean enlarge its inlet and outlet ports , i drill the inlet port 28mm , and also enlarge the exhaust port , polish it to near chrome finish ,
second i buff polish the piston head , valve face and combustion chamber
third i increase the compression ratio by grinding the face of the head , mean refacing , and using the original japanese gas kit which is very thin and compress more than a local one while we tighten the head nuts
forth i do a alteration in carborator butterflys , its a long process and cant be explain all here , but i try my best to explan ,
i notices that carb has 2 butterflys , one is small and other is large , the small one works while car is below 60 to 70 , after that the other larger butterfly opens , and both works at the same time , the small one opens with the press of acclerator padel while the large one opens as the vacum increses in carb , but the vacum lines (with in carb) are blocked with carbon and there efficiency reduces by as your car goes on high milage and some times goes to near zero , first of all you must find that vacum passage and clean it , and second you can enlarge that passage , i percenally trace that passage and drill it with a very tiny bit ( i do that almost 5 year before so i cant remid exzact size) , keep in mind that the second bigger butter fly is openned by a diapharm which interns takes vacum through the carb
i do all these things and belive me my car touches 160 and still ask more ,
do check my forum
https://www.pakwheels.com/forums/performance-modification-tune-up-preventive-maintenance/181721-cultus-engine-body-overhaul-rebuild
thanks
