Every V8 engine we have ever dismantled was suffering from all 8 cylinders leaking compression into the valley (Crankcase) of this engine, thus resulting in 'Crankcase pressurization' that causes many V8 engines to suffer from excessive sludge build up and constant oil leaks around the centre 'Valley' tin gasket, Crankshaft seals, Distributor seal and Rocker covers - this problem can be fully alleviated by the fitting of composite style head gaskets.
These gaskets are made of alternate layered material and are slightly thicker than the standard tin gaskets (lower compression by a factor of 0.7-1) and when fitted on the V8 engine will normally alleviate the leakage problem completely, thus curing compression loss, Oil contamination and un-relinquishing Oil leaks. We recommend the use of composite gaskets on most engines. Rover are now using Composite valley cover gasket, and Composite head gaskets also, in addition The Rover V8 engine is being constructed with the 8 outer head bolts omitted, thus further ensuring a gas tight seal. (exceptions to this advice are available for higher performance engines)

Head Gaskets
Left is the composite head gasket & right is the std. shim steel one. Although this is a far better gasket than previous attempts, it is worth noting that a good quality engine rebuild could safely use the original shim steel gaskets to retain compression if the outer head bolts are not fully torqued (being the main cause of the leakage problem).