Well......and I am not bashing here, simply pointing out facts. So here they are. The 51-53 331s were the least desirable of the early Chrysler Hemis. Here are the reasons.
First, as you have already pointed out, they have integral bellhousings cast as part of the block. This limits what the engines can be put into, as you need more area at the back of the engine to accommodate the cast in bellhousing, as it is not shaped like a conventional bellhousing. There was a kit with instructions offered that allowed you to cut the cast in bellhousing off and drill and tap the back of the block to turn it into a conventional bellhousing. That was however, a very tedious job and required a perfect cut. PITA to say the least unless you solicited the services of a machine shop which could be costly.
Secondly, the 51-53 Chrysler 331 heads are the absolute worst in terms of flow. They have tiny round exhaust ports as opposed to the later style much larger oval exhaust ports found on the 54 and up 331, 354 and the later 392.
Both those things said, here's the good news. It's STILL an early Hemi. An early CHRYSLER Hemi. They were the most desirable of all of the early Hemis......even with the two shortcomings mentioned. It's still a Hemi. Those "worst" flowing heads still outflow most other OHV heads of the era, plus the engine still has the Hemi look that cannot be beat. I think your dad's neighbor is right on the mark with his price. I would not go much under that, because as I said, it is still a Hemi.
Oh and even with the block needing sleeves, it's still a good deal. As long as it has no unrepairable cracks elsewhere and the sleeves will fix it, it will be fine.
