Are 3.8L and 4.3L interchangable?

[Lurch]

I am looking to port and polish the heads on my 1998 3.8L Buick LeSabre L36 engine, but since this is the first time I am doing a P&P job I dont want to mess up my original heads. So what I was thinking is if I get an extra set of heads, if I mess them up my car will still run since I didnt take my stockers off and mess them up. But that got me to thinking... maybe the 4.3L heads have bigger intake and exhaust valves than the 3.8L. Does anybody know if I can pick up a set of 4.3L heads, P&P them, then just put them on my engine? Any help would be appreciated :)

[Teufel Hunden]

a 4.3 is a completely different motor. Nothing between the two is interchangeable.

[Lurch]

That's what I figured, I just wanted to make sure. Oh well. Ill just have to get some different L36 heads then. Thanks

[Mad Bunny]

Well.... I think you can use the dip stick....