Hi Dave and All: Apparently most, if not all, 300F blocks do NOT have the HP. I have no idea why this is the case. I personally have never seen one that I knew to be original which had the HP. Perhaps George Riehl has, as he has seen more that I. On the "up" side, the lack of an HP does make it easier to come up with a "proper" block for a 300F if one is needed! Dave, the date on your block, 3-2, would mean the engine was built on March 2, 1960. since your car was scheduled for January 12, and actually shipped on February 10, It does not seem that this engine/block could be your car's original. It is odd, however, that the casting date is so much earlier than the assembly date, and that the bearing shells seem to go along with the casting date. Was this engine partially completed as a short block and then sidetracked in the engine plant for a few months? We will never know, will we? The "starting" engine ID numbers of 8-4 means that 1960 P series engine production for all models started on August 4, 1959. Hope this is of some help. 300ly, Gil Cunningham Tallahassee, FL In a message dated 1/7/2006 5:04:28 PM Eastern Standard Time, Fnnutz@xxxxxxxxxx writes: Confusion reigns folks. Several opinions have been offered up re the HP stampings on 413 blocks. My 300F block is stamped P-41 and 3-2 on the boss. 2120529-3 R L 11-30-9 cast in the block one side, and 2120529-3 R L and a clock pointing to the 3 on the other side. There is no sign of any HP stamping. Does this mean that my block may NOT be the original block? The Torqueflite is correct numbers for a 300 box, and the engine had the original steel shim gaskets dated 1959. Can anyone shed some light? Do 300 blocks ALL have HP stamped on the boss......or not? One more thing. On about Page 5 of my 1960 Service Manual( not numbered) is a heading License Data. Lists starting vehicle numbers for Detroit and LA built cars,and starting engine numbers.Plus 2 pics of where to look. It says: Starting engine numbers will be as follows: Windsor PR-38 8-4 Saratoga PR-38 8-4 New Yorker P-41 8-4 Chrysler 300F P-41 8-4 Imperial P-41 8-4 Starting engine numbers?? What the heck can that mean? Mine is stamped 3-2 and I took that to mean Feb 3, as the build date of my car was Feb 10. Sometimes I find the Chrysler tech data somewhat confusing. Dave in New Zealand. Thanks, Dave in New Zealand. [Non-text portions of this message have been removed] To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm Yahoo! Groups Links [Non-text portions of this message have been removed] To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/