Intake Manifold Gasket Leak ?

[PHOENIX]

Some of you may have read about my problems with oil in cyl. #4.

Quick review:
Engine crate 350 ($1300 one) w/ est. 50,000 miles.
Compression 150 psi all around
Valve stem seals checked and good on cyl. #4
Truck runs fine with new spark plug.
After 10-15 miles of driving the spark plug gets oil on it and doesnt fire correctly causing engine to run rough.
Once oil is on the plug it still runs ok until 3000rom at which point it becomes rough.
With a friend following me he can notice a small amount of smoke out of my tail pipe under heavy acceleration (the oil being burned).
If I put in a new plug it runs fine again for awhile (10-15 miles).
Also checked plug wire and even tried another one, distr. is new msd.

I pull the intake off and there is a crack in the intake gasket at the bottom intake runner of cyl. #4.
Its not a big crack but I noticed it right away (Ill post pics later).
I am guessing this is how the oil is getting into the cyl. I plan to replace the gasket and try it out.
Does this sound like a likely cause to you guys?
If the intake gasket doesnt fix the problem then I will pull the head and replace the piston ring.

I want a great quality intake gasket, can someone recommend one?