I was wondering if anyone could enlighten me on some much needed info regarding a 351 Windsor. I have heard that the 1969-1975 351 Windsor blocks are more heavy duty (beefier)another words have thicker cylinder walls that kind of thing compared to later model 351 Windsor, Is this true? Also, if this is true what yearswere the more beefier 351 Windosrs made (I have heard 1969-1975), but I really dont know for sure. Your input and help is appreciated.