Buick 225 vs 231

Hello all,
I'm going to be looking at some parts jeeps in the next couple of days and I was wondering if there was an easy way to determine if I'm working with a Buick 225 or a 231 engine. The guy who's selling the parts says that both of the parts jeeps are from around 1970 or so, and that they both have the v6's. I'm just not sure if maybe at some point the original 225 was swapped for a 231. Could someone post some pictures of both or give me some areas to look for that distinguish one from the other? Thanks

 

cool- ran my #'s through the chart: Engine cast # 9901503, engine # DRH 108. So my engine was made Apr 18th of 69. My jeep I believe was made around Sept or Oct of 69 and is registered as a 1970.

 

Anyone have an updated link for this? I tried plugging in .net in place of .com and it didn't work?
thanks
Edit:

I found this for the 231 on here:
http://www.gnttype.org/general/v6hist.html

Still unable to find the above link

 

I found it as .doc format with Google.

Here's a pdf: http://nmr.mgh.harvard.edu/~reese/BuickV6CastingNumbersandInternalSpecs.pdf

 

Thanks for the link!