cles ▁and ▁M idget s ▁were ▁also ▁rec urr ing ▁divisions ▁throughout ▁the ▁ 1 9 5 0 s . ▁ ▁Notable ▁D ri vers : ▁Tommy ▁H inners h itz , ▁Johnny ▁Thom son , ▁Johnny ▁Mack ison ▁Sr ., ▁Dick ▁Tob ias ▁ ▁Notable ▁R aces : ▁Horn / Sch ind ler ▁Memorial , ▁NAS C AR ▁Grand ▁National , ▁Ind y ▁S we ep st akes , ▁M idget ▁ 1 0 0 ▁Lap ▁Championship ▁▁ 1 9 6 0 s ▁ ▁The ▁ 1 9 6 0 s ▁saw ▁a ▁major ▁evolution ▁of ▁the ▁d irt ▁track ▁racing ▁centered ▁in ▁Central ▁Pennsylvania . ▁ ▁The ▁ ▁Fl at head - power ed ▁coup es ▁of ▁the ▁late ▁ 1 9 5 0 s ▁gave ▁way ▁to ▁Mod ified ▁stock ▁cars ▁and ▁their ▁more ▁powerful ▁engines ▁proved ▁a ▁bo on ▁to ▁The ▁Gro ve ▁with ▁its ▁long ▁straight aw ays ▁and ▁tight ▁turns ▁ ▁Origin ally ▁built ▁on ▁stock ▁frames , ▁the ▁full - s ized ▁pre war ▁cou pe - b od ied ▁Mod ified s ▁were ▁power ed ▁by ▁O H V ▁V 8 ▁engines . ▁D ri vers ▁like ▁Bobby ▁H ers h ▁and ▁Johnny ▁Mack ison ▁Sr . ▁were ▁frequent ▁visitors ▁to ▁victory ▁l ane ▁in ▁the ▁early ▁ 1 9 6 0 s . ▁By ▁ 1 9 6 3 , ▁the ▁Mod ified s ▁continued ▁to ▁evol ve , ▁now ▁with ▁still - recogn izable ▁stock ▁bodies ▁which ▁had ▁been ▁narrow ed , ▁cho