My 360 sounds like a sewing machine

So I finally got my 360 in my 72 Dart wrapped up abs took her on a maden voyage just around the neighborhood. Things were all good, oil pressure was good, temp was good, just a few things like timing and kickdown to be adjusted. Me being a little over cautious on my first engine build, noticed it sounded awfully like my solid lifter slant 6 previously: a sewing machine at idle to around 2000+ RPM.

360, RV cam. Hydraulic roller (factory roller block, not Magnum)
Stock non adjustable rocker shafts
Custom length pushrods for 050" preload
Stock Melling hydraulic rollers
Stock valves
Rebuilt iron heads, 9.5:1 compression.

Oil I am using is Castrol 5w30 Dino oil. It sounds like it at warm, and most likely when cold (I honestly can't remember). Oil is definitely getting to everything. I might have a touch too much oil, like a quart extra(I'll have to drain it). I checked pushrods, all are rotating and are straight. I tried to push on the lifters and they felt solid : does this mean they are pumped up? Rockers didn't have excessive wear. Finally, I checked the valves with a straight edge and a flashlight... And there's light shining on the exhaust valves. With a feeler gauge, they appear to be 015" shorter than the intake, uniform between all of them. Could this be my issue? When I went to measure pushrods, I measured about 6-8 of both intake and exhaust and took the average. I know I've read many problems with hydraulic rollers, but it was mostly with retrofit stuff. I just want to make sure there's nothing wise I should check. Perhaps I should get some pushrods with an additional 015"? Engine sounds great otherwise, and the oil change after the initial run showed nothing but break in stuff.