I'm buring oil on a 406sb with about 5k. It always has and I fear the rings never setup. I swapped the heads and that didn't help so the valve seals weren't the issue nor head. I seems to do it at startup and if you rep it. Especially when you shift on a decent to hard pull. I know it leaks a bit of oil on the front seal of the manifold but not on the head sides. The exhuast has a light popping when you let off and let the gear your in cause a deceleration. i'm planning on changing my plug wires and plugs this weekend.

Sounds like the intake is not sealing,drawing oil from the lifter valley,and causing a vacuum leak making it go lean.That's what I would check first.

im curious, are you using the rubber gaskets under the front and rear of the intake manifold?

i always throw them away and run a bead of silicone across to each intake gasket. ive had problems with getting the intake manifold to seal when using these gaskets.

just a thought

I used cork gaskets on the front and back of the manifold. Can a vacuum leak occur there? I thought it had to be on the heads sides int/exh?

It does have to be on the head side to cause the vacuum leak, though I always use silicon on the ridges.

See if any of the intake bolts are loose, and spray starting fluid around the intake base with the engine running. If the engine revs a bit you've got a leak on the outside. Spray some inplace of the breather, same thing. Rev = leak.

no it wont leak there, but ive had problems with those gaskets not allowing the intake to seal on the head. ive also ran into where these gaskets wouldnt allow me to get the intake bolts into the head, on my biscayne i had to remove the gaskets before the intake would sit low enough to get the bolts in (heads were milled).

i have no idea if this is your problem at all, but it does sound like your intake isnt sealing properly. i know that it is very common for people to toss the rubber/cork gaskets and run a bead of silicone under there because the gaskets are nothing but trouble.

I will try the starting fluid idea first. It has fouled some plugs as well but the wires are burnt in a few spots which I will replace this weekend as well.

that is a good idea to try first, but if the leak is in the lifter valley (which most likely it is due to the oil burning) this test may not show any results.

you might also try to put your hand over the carb while the engine is running. if the engine stalls you dont have a vacuum leak, if it keeps on running you have a leak. depending on how bad the leak is this test may not work either, but its worth a try.

Well something is happening. I just don't think it is the rings. It comes out of both the tail pipes. It did it with the old 441 heads and now with the afr heads.

do you have a HV oil pump in it?

Tom

yep a high volume oil and fuel. I want to say it is a carter but I would have to look I built the motor a long time before I put it in.

Are you running a pcv valve? If so and you don't have a baffle in the valve cover it is in you could be sucking oil into the base of the carb. Typically this will show when you get on it and you'll have a hard time getting rid of a detonation (pinging) problem...

If DJD is correct then pull the pcv hose off of the carb. If there is oil in the end of it that could be your trouble.