Originally Posted by SSDiv6 (Post 615175)

NASCAR engine blocks, have closed camshaft tunnels; therefore, the roller cam bearings, camshaft and lifters were always flooded with oil. The initial idea for the use of roller bearings was to reduce friction. Nevertheless, no one expected valvetrain frequencies and harmonics to generate from its use.

Originally Posted by 1347 (Post 615236)

Junior Johnson was running roller bearings in a stock Chevrolet block in 74. I saw a stock open tunnel block at Smokey Yunicks shop from the 70s or 80s also with roller cam bearings. Maybe Jenkins saw harmonics, but the Nascar guys were cheatin with them before with success.

Originally Posted by HP HUNTER (Post 615126)

Carl

Some years back I had a contract to build Winston West 9.1 comp 390 carbed 358 engines. We were quite sucessful and won several races, every engine we built had roller cam bearings, but also were dry sump. I never saw any weird stuff going on in those engines, they made right at 600 HP. Not going to say there was no harmonics, but we never had problems. We also built some with 55 MM babbit, I never saw any difference on the dyno, I did like getting rid of the oil leaks.