What are the major diferences if any between thease 2 engines? I have a 350 in my nova and is not original engine. I took my oil dipstick holder up to the parts house to try to replace it with one that was not bent (why o why did i do that.... moveing on now)and the one that i took off my engine is slightly smaler in diameter than the one that every parts place in town trys to sell me. Yep i took it with me for comparison. Is it possiable that I have a pontiac motor and not a chevy? What are some other possiabilities?  

I ran into the same problem a few years back....It seemed my problem was I had a right side dipstick and got a new left side..or vice versa. I cant remember(gettin old), but they were different sizes. That my be the problem you are having....maybe not.