  Four newest CCD eclipse timings of the white dwarf for polar UZ Fornacis and
Six updated CCD mid-eclipse times for SW Sex type nova-like V348 Puppis are
obtained. The detailed O-C analyses for both CVs inside period gap are made.
Orbital period increases at a rate of $2.63(\pm0.58)\times10^{-11} s\;s^{-1}$
for UZ Fornacis and of $5.8(\pm1.9)\times10^{-12} s\;s^{-1}$ for V348 Puppis,
respectively, are discovered in their new O-C diagrams. However, the
conservative mass transfer from the secondary to the massive white dwarf cannot
explain the observed orbital period increases for both CVs, which are regarded
as part of modulations at longer periods. Moreover, the O-C diagram of UZ
Fornacis shows a possible cyclical change with a period of
$\sim23.4(\pm5.1)yr$. For explaining the observed cyclical period changes in UZ
Fornacis, both mechanisms of magnetic activity cycles in the late-type
secondary and the light travel-time effect are regarded as two probable causes.
Not only does the modulation period 23.4yr obey the empirical correlation
derived by \cite{lan99}, but also the estimated fractional period change
$\Delta P/P\sim7.3\times10^{-7}$ displays a behavior similar to that of the CVs
below the period gap. On the other hand, a calculation for the light
travel-time effect implies that the tertiary component in UZ Fornacis may be a
brown dwarf with a high confidence level, when the orbital inclination of the
third body is larger than $16^{\circ}$.
