350 built to break burns oil like its going out of style

[greenmonster]

I've got a 350 built primarily for sheer torque output, so it has KB flat top pistons, bored 40thou over, moly rings...882 heads and tons of goodies....after a year I decided more torque was necessary, so more parts and higher compression...and now when I load the engine down or climb steep uphills the back two pistons let oil past the rings....this is noticed around 3500 RPM and above...it never burns on start up or at idle or regular cruising.....could it be the crankcase is not venting enough and building up pressure, forcing it(the oil) past the rings at the back pistons??....any help would be great....P.S.compression is high and even on all cylinders and all gaskets new....everything but a leak down test has been done.

[thek5blazerman]

oil can be only coming from two places, valves or rings.
your valve seals may be leaking depending on whether they are good or not and how much play is in your valve guides. as with rings the only thing i can think of is that your piston rings arent seated correctly or the end gap is too big. depending on how much work you want to do, you could get some gapless rings from total seal, which are sold from jegs, summit, etc

[tom3]

Did you plane/mill the heads? Any chance your intake is not sealing up at the ports underneath and drawing oil from the lifter valley? That's about all I can think of besides the usual.

[Austin8214]

Let me ask you this. When you put the new head and intake gaskets on did you did you make the hole bigger for the water jacket. I have seen a few engines that people did not drill these out and what happens is the back two cylinders run hotter than the rest causeing more ware. GM used the smaller holes in the gasket to aide in warm up but if you realy run it hard then it is a bad thing. Hope this helps.

[MagicRat]

Holy ancient threads, Batman. This was started 3 1/2 years ago. Chances are greenmonster has fixed the problem.