Please keep in mind that this is my first time posting a question. However I need serious help. I have a rebuilt 350 engine with 383 heads. Oil is blowing out the dipstick tube, which I have been told is blowby and the result of bad piston rings. What I need to know is if this is correct or not. If not could it have anything to do with the heads. I didn't have this motor rebuilt the guy that owned it before me did. He told me that he didn't replace the piston rings or have anything done to the heads. If you use 383 heads on a 350 motor do you have to make any changes to the heads? This motor runs great, has plenty of power and doesn't have any other problems except the blowby's getting worse. Please help!

 

Could have something to do with the heads; the intake sealing surface especially.

Not familiar with 383 heads. That's a new casting number on me. Never heard of that casting. But all SBC heads bolt up to all SBC blocks (except LT1), so there's no compatibility problem, as such.

 

rings are probably badly worn....is your engine a tuneport 083 heads were stock on them

 

If you mean the heads came off a 383 motor, there really is no such thing as "383" heads - a 350 is a bored/stroked 350 motor, so they would be 350 heads. Basically, all sbc heads are sbc heads, there is no real designation between heads on any sbc, heads are heads, some better, some worse, but heads are all heads.