Large Block M 4 Series Engines dll llnnnnnnnnnnnnnnnnnnnnnn rl 396 427 454 CU IN Displacement slllllI nllllllnlnnnnlnlllllb Q To build a 396 cu in heavy duty engine it is necessary to 7 start with an RPO L 78 engine which has 4 bolt main bearing 4 caps and oil cooler provisions in the cylinder case This engine is built with the same large port cylinder heads and inlet manifold as high performance 427 s The RPO L 78 was rated at 375 H P in production and parts for increased A performance are available from the heavy duty parts list In 1970 the RPO L 78 engine was increased in displacement to 402 cu in by increasing the bore size to 4 l25 from 4 094 In addition the engine is now equipped with a low profile Vtyp aluminum intake manifold for improved hood clearance To build a 427 cu in heavy duty engine it is easiest to start with an RPO L 88 engine assembly which comes with Q aluminum cylinder heads or an RPO L B8 short block This 2 includes 12 5 1 compression ratio piston connecting rods I V with 7 l6 bolts which are 100 magnafluxed and coplated at V the pin end for floating wrist pins and chain drive camshaft g If you procure a complete engine assembly you also get 7 l6 V diameter pushrods and guide plates 1 I To build a 454 cu in heavy duty engine it is easiest to start with an engine assembly which comes with aluminum V cylinder heads or use a 427 bare block and build up This i I includes 12 5 1 compression ratio pistons connecting rods with 7 l6 bolts which are 100 magnafluxed and coplated at A N the pin end for floating wrist pins and chain driven camshaft Use 7 l6 pushrods as described above for the 427 an n i R V i i e ll l6 70 I x t Y r 1 A J K