Buick Professionals, I have to admit I need to get my act together as I have had a super outpouring of help on my quest to find an engine. However, my stupidity falls in the area of not telling everyone the full story. I bought a really great 63 Riviera, nice body with no rust, new interior etc, you know the story.... The engine was not original and I bought it that way. The seller and I looked it up in both Motors and Chiltons and identified the engine as a '61 401. No problem as I was fine with that. As I was tearing it down to rebuild it, I measured the bore as that of a dang #%$&@ 364! The engine has a center sump for the Riviera but a pump of a 401 to fit the pan. However, the 401 oil pump does not fit properly on a 364. Always a catch and what a cluster.... I would love to shoot the idiot that did this to this car. I examined the numbers closer and they where NOT ground off. I have had two other engine builders in the area look at this number and they even agree that it is original and verified that it is not looked up wrong. The '61 364 starts with a 3H The '61 401 starts with a 4H and the number is: 4HI02II87. I have a brand new set of .060 pistons for the 364 but I want to put a 401 in so my 2x4 intake will fit. The 364 is in great overall shape but, you get the picture.... The transmission is a dynaflow that was professionally rebuilt and shifts strong. So what I need is a 61, 62, or 63 401 that will fit my application. I do not mind a rebuilder. In fact, a short block would be fine unless there is a issue with the heads Last note/question: What is the difference between the heads of a 364 and 401? Thanks, Doug
