I saw a 69 L89 and asked if it was the original motor and the owner said it was. Upon closer inspection I saw that the block had the correct 512 casting number but then saw the letter T stamped behind the numbers. Does this mean that the block is a truck block? Thanks in advance.

 

Anything that was cast at the Tonawanda Foundry carried the "T" symbol cast into it, and the front block pad stamp code on all Tonawanda-built engines always starts with a "T", just as the pad stamp code on Flint-built engines always starts with an "F" ('55-'66) or a "V" ('67 - up).

 

How'd they get V for Flint anyways? I can see F for Flint, but V? ~Juliet

 

John, thanks for your reply. I was asking because I have seen other 427 blocks with the 512 CASTING # with a P stamped behind the casting #. Am I missing something?

 

Nobody really knows (yet) what the "P" adjacent to the 512 casting number means. The 512 block was introduced mid-year 1969 in anticipation of the release of the 454 for 1970, and has all the clearances cast-in for the throws of the 454 crank. The casting date was located on the side of the block until November 17, 1969, when it was redesigned with the "short" distributor tower in the lifter valley, and the casting number was moved to the left rear bellhousing flange.

In the early 50's, the "F" was used only by the old Flint Motor Plant (the old engine plant in downtown Flint that made only the 6-cylinder engines); the new Flint V-8 Engine plant opened in 1955 on Van Slyke Road north of Flint, and used the "F" symbol also, through the end of 1966 model engine production. The then-new computerized engine warranty cost tracking system couldn't tell the difference between an "F" 6-cylinder and an "F" V-8 (to assign warranty costs to the correct engine plant), so the new "V" designator was initiated for Flint V-8, and its use started at Flint V-8 for 1967 model year engine production. They probably didn't have much choice of letters to pick from, as almost all letters were already taken by all the GM assembly plants; for instance, the Lordstown assembly plant was built in 1966, and its letter is "U" - Flint got the next available letter in 1967, which was "V".

 

Hmmm, the V works with Van Slyke too. :D Thanks for the history John. :) ~Juliet