▁ratio ▁was ▁raised ▁slightly ▁from ▁ 8 . 9 : 1 ▁to ▁ 9 . 0 : 1 ▁due ▁to ▁a ▁change ▁of ▁the ▁p ist on ▁design . ▁The ▁shape ▁of ▁the ▁in let ▁ports ▁were ▁also ▁changed , ▁from ▁an ▁O - port ▁design ▁to ▁a ▁D - port ▁design ▁which ▁improved ▁the ▁flow ▁characteristics ▁of ▁the ▁heads , ▁the ▁old ▁ 4 0 ▁D FA V ▁We ber ▁car b ure tor ▁that ▁was ▁pr one ▁to ▁over - f uel ing ▁and ▁resulting ▁bore ▁was h ▁was ▁replaced ▁by ▁the ▁ 3 8 ▁D G AS ▁We ber ▁Car b ure tor , ▁the ▁air ▁filter ▁housing ▁was ▁also ▁changed ▁and ▁later ▁around ▁ 1 9 7 6 ▁and ▁a ▁hot ▁air ▁int ake ▁was ▁added ▁consisting ▁of ▁a ▁metal ▁pipe ▁running ▁from ▁the ▁top ▁of ▁a ▁plate ▁w eld ed ▁on ▁the ▁exhaust ▁manifold ▁or ▁header ▁to ▁an ▁opening ▁in ▁the ▁air ▁int ake ▁to ▁prevent ▁the ▁car b ure tor ▁from ▁ic ing ▁and ▁making ▁the ▁engine ▁warm ▁up ▁quick er , ▁the ▁car b ure tor ▁was ▁also ▁modified ▁again ▁and ▁a ▁return ▁style ▁fuel ▁system ▁was ▁adopted ▁and ▁a ▁vac u um ▁operated ▁cho ke ▁in ▁the ▁air ▁filter ▁housing ▁were ▁also ▁added , ▁this ▁and ▁a ▁Pos itive ▁c rank case ▁vent ilation ▁( PC V ) ▁system ▁were ▁also ▁early ▁forms ▁of ▁em issions ▁control . ▁The ▁cam sh aft ▁g ear ▁was ▁also ▁made ▁slightly ▁stronger ▁by ▁using ▁steel ▁with ▁n yl