Ok, so I've tried researching this extensively and there is plenty of info about this on this site, but does every 575sci motor come with a flat cam and lifters stock? The reason I ask is when looking at my mercruiser gm engine identification manual it states states that 2000-2001 and 2002-up are gen VI block with roller set ups. Is this an error in the manual. I'm curious to y they would keep using the flat cams and lifters anyways. If u scroll down u can find it at this URL http://www.marinemechanic.com/merc/d...lockcodes1.PDF

They're all flat cams.

They're already a the limit of an XR drive...the cam is the governor.

They respond well to a HR cam

That's what I thought. I appreciate the reply. If the motors have only very minimal break in time ran on them but have been sitting for 3 years would going through first start up protocol be required again? Or as long as using correct oil should it be fine? Just dnt wanna chance wiping a lobe out....

I would change oil and filter , use either an additive or oil that has flat tappet additives in it already , then I would prime the oil
pump and fire it up right away and hold RPM's at about 1800 for about 10 - 15 - minutes .

Good info guys. Maybe valve springs need changing also after sitting for 3 years some being in a bind?

YES!!!! Change the springs and I would get away from the flat tappet as soon as you can. They are junk and will end up costing you a rebuild if you want to chance it. You can buy oils with the zinc those cams were designed to run with but I still don't trust the the flats.

I would certainly change the springs, especially if the engine has been sitting and hasn't been turned over in that time period. Some of those springs have been compressed for 3 years. As mentioned, it a damn good idea to get away from the flat tappets if budget allows. You can put a nice hyd. roller in it and really wake it up.
Let me know if we can help.
Eddie

I would certainly change the springs, especially if the engine has been sitting and hasn't been turned over in that time period. Some of those springs have been compressed for 3 years. As mentioned, it a damn good idea to get away from the flat tappets if budget allows. You can put a nice hyd. roller in it and really wake it up.
Let me know if we can help.
Eddie