improve oil return

[blkchevyz]

my heads have been sitting for many years, i was going to take them apart to block them to make sure they are still strait and to help with sealing.
while i have them apart i was thinking of de-burring the return holes to aid in drain back. anything else i should do? the heads flow in the 280s so i'm not messing with the runners. but should i lap the valves since i'm removing them? removing casting marks from the valley?

[shownomercy]

glyptol

[blkchevyz]

i think i would want the heads hot tanked before i did that. hate for it to flake off into my oil.

[quik95lt1]

if they are stock heads you can drill out the oil drain holes to 3/8" IIRC.....bevel and chamfer the edges of the holes to help the oil drain....also make sure the head gasket is not covering the hole so it can drain well into the valley...also on some I have modified the block with a groove so the hole isn't partially plugged up in the back corner.....glyptal will help in the engine valley but ive never done heads with them

[95slowmaro]

i cleaned up my drainback in my heads and made it smooth so oil could easily return to the lifter valley, BUT i found that when i put the heads on my block with the head gasket, the head gasket greatly blocked my oil return holes.. so i had to run a dremel in there and actually trim the head gasket. im not sure if it was just the brand head gasket i used or what, but it kinda irritated me.

[blkchevyz]

thanks for the tips. didnt even think about the head gasket slowing things down.

[95slowmaro]

yeah double check it before you physically bolt it down.. that way you can trim the head gasket away from the engine to save the hassle of having to cover everything up so you dont get crap everywhere