Accurate Freq Measurment

[Terry]

I am using a PIC to make a very accurate (sub hertz) frequency measurement of a 4 kHz signal in as little time as possible, about ~ 100msec. I am using TIMER1 to measure the period of 400 cycles of the 4kHz signal. I am starting Timer1 on a rising edge of the 4kHz signal, keeping track of the number of cycles and then stopping Timer1 on the 400th cycle of the 4kHz signal. I then have a count and number of rollovers of the timer from which I calculate the frequency in a computer, not the PIC. Below is the code of my technique. The question I have is there a better approach to taking advantage of the PIC’s hardware Timers and/or capture compare module, such to improve the accuracy and to do this in the background. The code in currently for the PIC16F877, but I can easily switch to an 18F part.
Thanks in advance for the help,
Terry