Is there a difference between the two?

 

The ONLY difference is the cam. Si less torquey, more top end power. DX less peak power, and torque comes a little quicker.

I used a Si head on my DX D15b2 block and EVERYTHING is the same; ports, vlaves, springs, and everything else except the cam.

 

yup, the factory casting numbers are the same

 

ive also heard that the Si head uses better springs....and if you get DX springs from Honda they have been replaced with Si ones. you can always look up part numbers to see for sure.

 

cam, valvetrain.

the d15s most certainly do not share the same valvetrain as the a6

 

Thanks guys. I'm asking because my friend who now owns my old Civic DX is thinking about converting it to an Si.