Big block casting number help

[Jon H.]

I am rebuilding the original motor in my 68 corvette ans I noticed a T casted in the back and was just curious what this stands for. My guess is Tonowanda but I am not sure. Thanks in advance

[Joe L.]

Re: Big block casting number help

Jonathan------

Yes, Tonawanda, NY is what the "T" refers to. Until 1985, all cast iron big block engine blocks, heads and other parts were cast at the Tonawanda foundry and machined/assembled at the Tonawanda engine plant which was located right next door.

After 1985, all big block cast iron components were cast at Defiance, OH and shipped to Tonawanda for machining/assembly. That practice continues to this very day, although the Mark IV big blocks, and components thereof, produced from 1965 through 1990 have not been manufactured in many years. Mark VI and "Mark VII" are the ones currently produced.

[Jon H.]

Re: Big block casting number help

Thanks for your help!