300 I-6 engine identification?

[furnitureguy-123]

I am trying to identify the motor in my '66 stepside. The po said it was an 80 model. I'm not sure. Here are the #'s off of the block. Can anyone help me id this motor?
D5TE-60-8 (or s)-AA. Does the D5 mean 1975? Thanks for any help!!!

[fordman]

the castign for that block was amde in 1975. it is for a Truck. and it is an engine. d5TE 1975 truck engine. that is what the numbers in the casting of the block meant. the rest has to do with application of the use of it. 240 and 300 were the same block.