What are the differences of the REV numbers stamped onto heads?

1 REV 9
1 REV 12
1 REV 14

Thanks

Good evening Board I have a 04 Polaris 700 twin carb model that i re did the top end New pistons head gasket and base gasket put it back together and stated it up drove it ran good for a few minutes then it started losing power checked fuel delivery seems to be doing good cleaned carb somebody was in there ahead of me they took the slot of the pilot jet so i cant get that out but I cleaned it idles fine but when you go to give it throttle it dosent like it and you can hear it popping back through the carb thought maybe it has a faulty ignition system but found out it has been updated using the Polaris update kit new stator flywheel coil voltage regulator cdi box I am lost right now pulser coil ohms out good .oh just for your info the reason the top end was replaced was I was servicing it and found antifreeze in the oil.So torn it down and you can see where it had seized can somebody give me some areas to look out need to get this fixed customer wants his machine back sorry for the long post any help would greatly be appreciated

What should oil pressure be at idle ? Mine is 2lbs. At 5000rpm 25lbs. Installed new oil pump when I replaced the crankshaft, cam, lifters. Running 5w-40 oil Rotella.

new to Polaris got it with a bad cam got new cam kit now the fun part how to time it I found the timing dots on the two gears and the gold color chain links where does the timing marks need to be.:question::question: