I have two different sets of heads for my 350. All 4 heads have 333882 as a casting number. My question is why would one set have 1.94 intake valves and the other have 1.72? I also have a set with the same casting number that came off my truck and one had one size and the other the other size. I was under the understanding that a casting number would have the same size of valves and this is what is confusing me. Can someone please help with this and explain what the difference would be?
Those heads were used on both 350 and 400s, the latter using the biggers valves. 882s are pretty good heads, for smog heads. Little port/polish, and they flow good. Look for steam holes between the chambers to the two apart.
a casting number is just that ... a CASTING number
It has nothing to do with the machine work done to the raw casting to make it a completed head .... it could all sorts of different sized valves put in it depending on application