Originally posted by Skid Jackson
Could you just leave everything stock and do some head work and Get the same result as a big bore kit. Is head work ultra pricey?
Sorry Skid, must have missed this one earlier.
IMO NO, dollar for dollar on this engine a larger bore is a better deal. The pros of doing a plated overbore :
- you can tighten up the squish clearance, which this motor needs
- the bigger bore shifts the torque peak down a few hundred rpm helping to prolong crank and valvetrain life
- the increase in bore will increase intake velocity at the same relative rpm and helps mute the small torque trough that currently exists at low rpm. This effect is even more pronounced with OS aftermarket head pipes which tend to punch a bit of hole in the torque curve around 3500-4000 rpm
The horsepower gains that can be derived from head work and cam/valvetrain changes on this motor will tend to favor high rpm at the expense of low rpm torque. The extra rpm required to take advantage of these changes does nothing positive for overall reliability.
Done correctly there is no cheap
reliable (HUGE emphasis on reliable) way to make a big change in airflow with this design.