I just bought a 1994 chevy 1500HD with a 6.5TD.The truck has 240k on it, in excellent condition, but the motor was replaced by a GM crate 6.5TD..Now my question is..What year 6.5 do i know i have? he said he got it replaced in 2003, I don't know the difference between a 1994 6.5 and a 98 6.5..can someone lend me a helping hand here and help me figure out what year i have..obious stuff on the motor, serial numbers/where at?, etc..thanks advance..

-Eric

this may not relate but i will share it anyway.
On my 6.5 NA, looking at the place where the block meets the trans, on the passenger side, there is a casting number that says D149 and i called GM parts division and they said the D represented the month of the year (d being the fourth letter, thus representing the fourth month, april) then the 14 being the day of the month, and the 9 being the last digit of the year. Thus, april 14 1999 in my case. It could also have meant 1989, so
there was also another set of casting numbers on the drivers side of the same place which i showed to a GM dealer and the info they brought up confirmed that the D149 part was correct and that it was 1999. In my case i was trying to determine if it was a 6.2 or a 6.5 and i had to basically use both sets of numbers and two different GM dealers to get all the info together to find out that my van had an engine with very low miles and it was a 6.5.
Paul