Japanese engineers made that K6 engine for this car after doing some engineering... its our stupid PS who slapped a useless F10 in it.
Fuel economy of K6 will be equal or better than mehran f8b.. K6 has enough power to carry the Alto easily.. there are numerous such swaps in market already cause these engines are easily available than the f8b.. K6 is a simple bolt on swap, and cheaper than f8b