why did merc go with a solid roller setup,good question,why does merc do half of the things they do.my guess is so they can sell more parts.the turbo engines are dual overhead camshaft design,no more pushrods.

Mike,
I have looked at a couple of the past ; post in this "thread". Talking about needle bearings falling out, the only times needle bearings fall out is from bouncing the lifter, lifter hours beyond service. I have seen; hydraulic roller lifters drop the bearings out at removal. Spring pressures are limited on hydraulic roller lifters, and you can push their limits with spring pressure, RPMs, valve, retainer weight and lobe design.
I think Merc wanted to cover their warranty, with the solids even with a less aggressive cam lobe. You have to remember; Merc likes a .375" valve stem and non titanium retainers, which adds to mass on the valve side. Madara, can give his; input on this subject.

Any thoughts on bushed lifters?

What do you guys think about rev kits for roller lifter motors?
Even if you are not turning high RPM's - wouldn't it help keep the roller ON the cam lobe and stop the roller slamming down on the lobe. I was thinking about running a rev kit.

The machine shop is telling me not to waist the $ on bronze bushing the lifter bores. I plan on turning 6500 - 7000 RPM.

You might look at the stainless shaft rockers if you haven't already.

Don't waste your money on lifter bushings unless you are going 55mm Cam and big lifters. Rev kit think its a thing of the past. One more thing to break.

I run the 904's with no lifter bushings either. A good quality rev kit isn't a bad idea, but a nice tight lash solid deal, with bushed axle lifters can be incredibly reliable too. Anybody who is truly making 1200hp+ with a hydraulic roller is leaving lots of power on the table.. Opening the exhaust valve against all that pressure is a biatch.

Sorry, I was taking about the bushings in the lifter rollers, not the bores. Scattering needles in a block would be no fun.

In the case of the 1075, this allows them to have a 75-100 hr recommended rebuild interval. They assume that most will send their engines back to Mercury to be rebuilt. They get $22,500 per engine, so that's a bunch of money on a regular interval.

The turbo engines are completely different animals. They use dual overhead cams.