Modern 'rollers', be they hydraulic or solid can be made to rev high and live! Hydraulic rollers can push the 7000 rpm range these days. Solid roller lifters, in certain blocks not all, can be force fed
oil pressure to make them 'live long'. Lack of oiling on a street driven (lower rpm for much of the time) has been the killer of solid roller bearings. With the new pressure
oil feed, thats no longer an issue. High tech hydraulic rollers can see some lofty rpms these days.
BUTT, there is a significant cost to either approach, this is NOT a cheap solution. Even standard roller hydraulic lifters cost considerably more than a flat tappet combination. Valve springs, rockers and push rods will still need to be matched for the cam/lift/geometry no matter which one you choose.
When I was rebuilding my motor I considered all the various factors and went with flat tappet at a max rpm of around 6400. Number one, I didn't want to rev the engine much higher than that for longevity reasons. The higher you rev, the shorter the life of the motor, period! Number two I wanted to control costs, which can VERY quickly spiral out of control when your building a motor. You find yourself in a trap like. Well, it's 'only' a few bucks more to do this or that. Those 'few bucks more' add up to a substantial number when the smoke has cleared! Spend your money wisely. I chose to spend big bucks on the pistons, for instance. Cost/benefit analysis, in my case, showed that was where the money needed to go.
A flat tappet cam would do a fine job for my projected horse power and combination street driving and some track use. The price difference sealed the deal. I get all the performance I want at a nice price. Flat tappets can cost more if your having the motor built for you because of the extra work involved initially 'breaking in the cam'. That extra cost MAY make it advisable to go with a roller because the cost of the parts may be offset by the cost of the labor to properly setup a flat tappet. I built my motor myself, labor was not an issue. I work for 37 cents an hour...
Labor costs and risk management are the PRIMARY reason professional engine builders recommend a hydraulic cam. Thats the PRIMARY reason. It is then justified by pointing out the 'performance' enhancements, high rev potential, blah blah blah. But don't forget the PRIMARY reason, it's easier for them to build, warranty and the parts profit level is better!
Proper breakin and careful
oil selection will gaurentee a long life for a flat tappet cam, as long as the engine itself holds together.
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