I have a bit of a mystery with my 1970 250 I would like to solve... Symptoms are engine burning oil only when accelerating motor (starts at about 1500 RPM) and no smoke at idle. I have narrowed it down to cylinder #3
as plus are wet with oil number 4 more so. Engine has a rebuilt cylinder head with low miles and excellent compression in all cylinders. I checked head torque at 65 ft lbs and all was good. Just as a precaution I replaced the stem seals on those cylinders, ones removed showed no issues. I have a few ideas such as defective oil scrapers on those 2 cylinders or more so possibly a cracked cylinder head. I have a bore scope and was able to look inside the cylinder but see no oil on top of piston (nice and clean) or signs on the intake valve. It appears on the threads of the spark plug and around the exhaust valve appears wet. Also I would like to add there is no puff of smoke when starting car just when getting up in RPM. Also having a bear of a time trying to lean out the carbs. Getting lots of fuel out of primary jets when rolling on throttle I'm sure it unrelated but thought I would add that in there despite thinking it would affect all cylinder equally. Thanks for any info.