▁providing ▁ ▁of ▁boost . ▁ ▁The ▁ 2 . 5   L ▁and ▁ 3 . 0   L ▁engines ▁share ▁the ▁same ▁block , ▁connecting ▁ro ds ▁and ▁ ▁bore , ▁differ ing ▁only ▁in ▁c rank ▁throw ▁and ▁p ist ons , ▁ 3 . 0 ▁L ▁p ist ons ▁have ▁a ▁length ▁of ▁ ▁and ▁ 2 . 5 ▁L ▁p ist ons ▁have ▁a ▁length ▁of ▁ ▁/ ▁ ▁. ▁ ▁Comp an ies ▁like ▁Special ised ▁Eng ines , ▁Es sex ▁engines ▁and ▁Ric ▁Wood ▁have ▁profession ally ▁built ▁and ▁developed ▁large ▁disp lacement ▁ 3 . 2 ▁L , ▁ 3 . 4 ▁L ▁and ▁even ▁ 4 . 0 ▁L ▁Con versions ▁and ▁forced ▁induction ▁convers ions ▁for ▁the ▁Es sex ▁V 6 ▁with ▁power ▁outputs ▁reaching ▁as ▁high ▁as ▁. ▁ ▁US ▁em issions ▁cert ification ▁ ▁In ▁ 1 9 7 7 , ▁Californ ian ▁company ▁Ol son ▁Engineering , ▁Inc . ▁was ▁contract ed ▁by ▁TV R ▁to ▁design ▁modifications ▁to ▁the ▁Es sex ▁V 6 ▁such ▁that ▁it ▁could ▁be ▁em issions - cert ified ▁for ▁use ▁in ▁the ▁United ▁States . ▁This ▁allowed ▁TV R ▁to ▁sell ▁its ▁Es sex - eng ined ▁M ▁Series ▁cars ▁in ▁that ▁market ▁for ▁the ▁ 1 9 7 8 ▁and ▁ 1 9 7 9 ▁model ▁years . ▁An ▁owner ' s ▁hand book ▁supp lement ▁for ▁US ▁Federal ▁models ▁indicates ▁that ▁the ▁em issions ▁control ▁system ▁used ▁a ▁catal yt ic ▁converter