cx to vx swap is it worth it?
 

i have a 94 cx civic and i found a complete running vx swap for 300$ what diffrence could i see mpg wise?

You won't . You mind as well sell it.
To me ..... ;)

Lucky find !!

I would think you could see a significant increase in FE.
From what I have been told from mechanics, the most tricky part is rewiring the cars wiring system for the new engine.

well could i see as much as 10mpg?? what more would i have to wire besides vtec and the egr?

Yes I believe you could see a 10 mpg increase if properly tuned. I think you have to rewire the O2 sensor. I think... I thought the cx had a 4 wire O2 sensor and the vx had the 5 wire.

To install the VX motor you will need to rewire the o2 sensor to a five-wire, run a wire to the ECU for vtec, and wire-up the EGR control box.

Other than that, it is straight forward. If you can't install the swap yourself, it would probably take a very long time to recoup the cost of paying someone to install it and in that case, just stick with the CX motor.

The transmissions/clutches/exhausts are the same between the motors, so you could sell those parts off of the VX swap in order to fund the swap.