1 9 7 1 , ▁another ▁rule ▁change ▁was ▁announced ▁for ▁ 1 9 7 2 , ▁and ▁Ferr ari ▁abandoned ▁further ▁development ▁of ▁the ▁ 5 1 2 M ▁in ▁order ▁to ▁focus ▁on ▁a ▁new ▁ 3 ▁Lit re ▁prototype ▁based ▁on ▁the ▁ 3 1 2 B ▁F 1 ▁car . ▁The ▁ 3 1 2 P ▁would ▁prove ▁fast ▁but ▁frag ile ▁in ▁its ▁debut ▁at ▁the ▁ 1 9 7 1 ▁Seb ring ▁ 1 2 ▁hours . ▁Further ▁development ▁over ▁the ▁ 1 9 7 1 ▁season ▁brought ▁increased ▁reli ability . ▁The ▁press ▁added ▁a ▁" B " ▁to ▁ 3 1 2 P . ▁Ferr ari ▁official ▁records : ▁Ferr ari ▁ 3 1 2 ▁P . ▁ ▁The ▁ 3 1 2 P s ▁with ▁the ▁flat - 1 2 ▁box er ▁engine ▁were ▁very ▁successful , ▁winning ▁ten ▁out ▁of ▁eleven ▁races ▁in ▁the ▁ 1 9 7 2 ▁World ▁Championship ▁for ▁M akes ▁and ▁deliver ing ▁the ▁title ▁to ▁Ferr ari . ▁Sc ud eria ▁Ferr ari ▁didn ' t ▁enter ▁the ▁ 1 9 7 2 ▁ 2 4 ▁H ours ▁of ▁Le ▁Mans , ▁as ▁En zo ▁Ferr ari ▁thought ▁that ▁the ▁F 1 - based ▁engine ▁could ▁not ▁last ▁the ▁full ▁ 2 4 ▁hours . ▁He ▁would ▁be ▁proven ▁wrong . ▁ ▁The ▁team ▁competed ▁in ▁the ▁ 1 9 7 3 ▁ 2 4 ▁H ours ▁of ▁Le ▁Mans ▁and ▁finished ▁second ▁behind ▁Mat ra , ▁which