Triumph Repair: Oil out the dipstick tube, crankcase ventilation, crankcase pressure

Question
I just converted a 1976 spitfire 1500 to a Webber downdraft carb from the stock system and emission controls.  Although the car runs much much better I now leak oil out of the front seal when parked and out the dipstick tube over 3000 RPM which leads me to believe that I have positive crankcase pressure which is not being relieved.  I followed the directions and connected the rocker cover vent hose to the air filter connection which is obviously not enough venting.  Understand that this car NEVER EVER leaked a drop of oil before this conversion 3 weeks ago.  What is the best solution to improve crankcase ventilation?

Answer
If the manifold doesn't have a fitting in it you'll have to pull the manifold and drill/tap a fitting to pull crankcase fumes into.   Ideally you'd have a catch bottle (completely sealed) in the vent line to avoid sucking oil into the intake.  

It may be enough to keep the oil in the engine.  The oil out the dipstick over 3000 rpm strongly suggests that rings may be marginal and you're looking at a rebuild in the not to distant future.  Do you know the history of the car?   If it's the original unrebuilt engine 34 years of service is pretty good.


Cheers,

Jim