This is a very much talked about subject. The camshaft choice depends on what will be done with the engine. Two things kill the solid roller lifter bearings, to much spring pressure and lack of oiling at a idle. The solid roller technology has come a long way since a few years ago with force fed roller lifters oiling the roller bearing and this is helping longivity. When choosen a solid roller camshaft you need to know the use street or strip, this makes all the difference in the choice of lobes and and spring pressure. The hydraulic camshaft are only used when the engine does not need to turn over 6300 to 6400rpms and there are a lot of the FE engines that guys do not want to turn higher than this and we are getting 650HP out of them by this rpm. The hydraulic flat-tappet and the hydraulic roller both suffer from this problem and it is due to the hydraulic lifter not being able to stay pumped up. The more you lighten the valve train and the thicker the
oil and the higher the
oil pressure the more rpms you will get out of a hydraulic camshaft. We have some hydraulic roller FEs that will turn 7200rpms but they have titanium valves and retainers. The solid flat tappet works well for rpm amd longevity but it has some draw backs as well. You need to break most solid flat-tappets in with lower spring pressure to let the lifter rotate and break the camshaft in. Once the camshaft is broke in you then add more spring pressure because with out enough spring pressure the valve will float and break. There are mild solid flat-tappet camshaft as well as aggressive lobes. The more aggresive the lobe the harder to break in and more likely to were out in the future. We have alot of cars come in with solid flat-tappets that have the lobes wore of because the builder did not break the camshaft in or installed to much spring pressure.
The question is much more complicated than which is the best? Which is the best for me and what am I willing to do for the extra power? Your engine builder needs to know your needs and power you want to make. The new solid roller stuff with the right lobes and springs will go 15,000 to 20,000 miles. You also have to remember the guys at the cam companys do not know much about a FE engine and the new blocks that are out that
oil throught the lifter galleys as most old blocks do except for most of the 427 blocks that were not drilled through the lifter galleys. Know what you want from your engine and then decide on the camshaft but make sure you have the right lifter, spring pressure, rocker system and pushrods.
We have been using the ceramic lifters in the NHRA stock eliminator and circle track engines for about 10 years now. We can run 200 seat and 450 lbs open pressure with them. We do this so we can turn the engines 8000 to 8500rpms with stainless valves and higher with titanium. Hope this helps a little on the camshaft issues. Thanks, Keith Craft
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