Context :

Aims : The aim of this work is to analyse the radio properties of the massive and dynamical disturbed clusters Abell 1451 and Zwcl 0634.1+4750 , especially focusing on the possible presence of diffuse emission .

Methods : We present new GMRT 320 MHz and JVLA 1.5 GHz observations of these two clusters .

Results : We found that both Abell 1451 and Zwcl 0634.1+4750 host a radio halo with a typical spectrum ( \alpha \sim 1 - 1.3 ) .
Similarly to a few other cases reported in the recent literature , these radio halos are significantly fainter in radio luminosity with respect to the current radio power-mass correlations and they are smaller than classical giant radio halos .
These underluminous sources might contribute to shed light on the complex mechanisms of formation and evolution of radio halos .
Furthermore , we detected a candidate radio relic at large distance from the cluster center in Abell 1451 and a peculiar head tail radio galaxy in Zwcl 0634.1+4750 , which might be interacting with a shock front .

Conclusions :