The Stovebolt Site Forums The Shop Area Engine Shop Breaking in a 305 SBC

Luckily, as far as I can tell, there are only 8 or 9 ways that oil can get into the combustion chamber and fewer then that on your 235. From what you have related I narrow that down to "2" ways for this to happen. A broken ring(s) or valve guides/seals. (You could have the rocker shaft on upside down, but I doubt that. That would possibly give to much oil to the valves.)

You said in a previous post that "The engine burns oil when warm. Most noticable after sitting at stoplights or idling.". This to me sounds like valve guides/seals. If, when you first start it up after it has been sitting fo a long period, it smokes profusely, then it is nearly always that it is valve guides/seals. A compression check will tell if it is the rings, which I doubt, unless for some reason they are not seating in properly.

One other thought is that the ring gaps are all lined up, but I don't this is the case. You did off-set the ring gaps, right?- RIGHT!!!