tooready

Any help would be appreciated! I have a rebuilt 403 with rebuilt 4a heads. Experiencing blue exhaust smoke, oil noted in intake runners, low vacuum = 12, and slight misfire!

I have tried original intake, the current aluminum intake with turkey pan several times thinking its pulling oil from lifter valley. Builder states heads were merely resurfaced for flatness, no excessive milling. I cant find any huge gaps with feeler gauge when sitting intake on heads.

block balanced and bored .030 over
arias pistons
heads ported/polished, resurfaced, new valve guides/viton seals/valves. comp cam kit 1441 1.6 ratio roller tip rockers, hydraulic lifters from comp cam
edelbrock 2711 intake with street demon carb currently installed
cam is comp cam xe 262 LSA 110 degrees, intake duration @ .05 lift 218 exhaust duration @ .05 lift 224
any help in solving this would be appreciated

coppercutlass

Do a leak down test and compression test and report back

olds 307 and 403

I know one guy actually used engine restore on a similar 403 fresh build. It seemed to help seat the rings, he was using oil as well. How many miles, did you up and down on the throttle to seat the rings?

BillK

Not sure if that would have a pcv system on it or not but an easy test for the intake is to remove the pcv valve from the valve cover and block the hole. Then go to the other valve cover and remove the breather or air tube. Then start the engine and take a can of 2+2 carburetor cleaner and squirt about a 5 second shot down into the hole in the valve cover. If the intake is leaking it will pull the fumes in through the crankcase and the idle will change a few seconds after you spray the carb cleaner in the valve cover.

Also take a look in the pcv hose first. If there is any oil in it at all that is probably where your smoke is coming from. Oem valve covers or aftermarket ?

Greg Rogers

The above seems correct to me. You shouldn't have oil in the intake unless being sucked in thru pcv ( or intake as you've already checked).