Guys, thanks to several posts here I've been able to find out a lot about a 350 I have. One thing I can't discover (and maybe it's not even worth anything) is the meaning of some casting symbols on the back of the block. One shows three letters - a 'T' a 'D' and an 'N' at a clock-type position of 12, 4 and 8 respectively with a pointer at the 'D'. Secondly there is a group of raised dots in a circle (10 dots) including a double dot at about the 3 o'clock position and a pointer at the dot in approximately the 4 o'clock spot. Ideas?
Those symbols are for use by the foundry. Supposedly indicate the shift when the casting was made and/or the number of times a mold had been used.
a friend of mine pulled a sbc from a 60s vette decoded as a 70s truck smog era engine he was sad and gave me the engine I love getting stuff from folks that care about numbers
To make sure your not being ripped off, make sure the SBC engine in question has Corvette valve covers. That will insure your getting an actual Corvette engine.
This web site is the best one to break down GM codes. Since GM sand cast their blocks I don't believe there is any of the mold used more than once other than the sand box. http://www.mortec.com Sent from my iPad using H.A.M.B.
Molds are used only once, but the pattern that the molds are pulled from are used thousands of times. At the start of the shift, someone changes the pointer and date codes on the pattern so that castings can be tracked in case something is wrong. Gary
The Jalopy Journal
