The Hot Rods in question tonight (6/29) were the musical not automative kind. The second of the season summer concert at Fremont Park featured a five-piece band playing early rock-n-roll hits. You knew the tunes if you listened to Top 40 radio in the late 50s and early 60s. The result: Lots of little kids doing their dancing thing complimented by more than average number of grey hairs in attendance bobbing their heads. All were saluting back-to-summer weather after yesterday’s freak rainstorm.