Blowing Blue Smoke after changing Intake and Carb

--------------------------------------------------------------------------------

Hello Everyone,

I've got a 1965 327/300hp that had a original intake manifold and abf carter carb before switching to a weiand action intake and a holley 600cfm carb with electric choke. The car was recently purchased and ran like crap hence changing the carb and intake combo. Before installing the new parts the car did not blow blue smoke and now it does (constantly light blue smoke out of BOTH TAILPIPES). I did switch it over to a pcv valve from the drivers side valve cover to the base of the carb. I blocked off the vent tube in the back of the motor with a plug which went to the original air cleaner. Now the air cleaner is vented to the passengers side valve cover which is baffled. I installed new plugs, wires, cap and rotor. It is timed at 10 degrees btdc at 700rpm. I hooked up a vacum gauge and it is showing 19 with slight movements BUT nothing radical. I pulled the new plugs from the drivers side of the block and they are all dry but with black carbon. After all this I put back the vent tube in the back as well as the pcv valve and it sill smoked. I did notice however when I shut the car off I hear a leak from the brake booster valve like a tire leaking air. It looks as if pressure is building up, what would cause that? Is that normal?


Don't have a good local resource to ask and thought maybe someone on here can help me out or had a smiliar problem or is familar with the older style block with the vent tube in the back. I'm looking for something that I could have done wrong that would cause this. I don't think if could be rings but maybe valve seals? Do they usually cause blue smoke out of both tailpipes?

Thanks for all your help!

I changed mine a few years back and had the same thing.after the 2nd set of intake gaskets i warmed the engine and retorqued the intake and all was fine. it was pulling oil thru the intake runners.

dont know for sure about the smoke did you check the vaccum modulator to the trans if it leaks oil can also get into the intake.the booster sound like it has a leak.while running the engine can probably overcome it but it should hold vaccum afterwords.

Could be the booster leaking or the valve that pushes into front of booster. It's a oneway valve and should hold vacuum in the cannister with engine off. Sounds like the intake is not sealed properly and it's sucking oil, since that's the last thing you touched.

I did changed the check valve and grommet on the booster and same problem. I also, while the engine was idling sprayed carb cleaner all along the manifold and the engine did not respond differently. Could I still have an intake leak?

Thanks!!

I did changed the check valve and grommet on the booster and same problem. I also, while the engine was idling sprayed carb cleaner all along the manifold and the engine did not respond differently. Could I still have an intake leak?

Thanks!!

Yes, you could.

I performed an intake/carb swap on the 350 in my '75 'Vette. I torqued the intake unevenly Left to right (or bank to bank), which caused the intake to to sit on an angle when viewed from the front. Therefore, it was drawing oil from the crankcase through the bottom of the intake runners on the left bank of the engine. The starter fluid check did not reveal a vacuum leak.

Make sure your intake is sitting flat and square when viewed from the front of the engine.