inline 6 chevy

I have a 65 chevy dually with a inline 6 .The block no. is 473483 / dka stamped on the pad. It has hei and small plugs. What year and size??????????.Thanks Henry. c25 heavy duty.

My info shows it to be a 75-85 250 cid I6...

Looking in the Chev Inline 6 book of Leo Santucci, it lists it as a Passenger car 1966-79 250 CID/4.1 L. without integral intake manifold, (cars used a low deck block, where trucks may have the high deck version.) That block number doesn't appear in any other list in the Casting Number list in this book, only the cars. The head if it hasn't been replaced would be 3895052. (As a point of interest, the head on the other hand was used in the trucks from 62-79 on the 250, and from 67-90 on the 292.) Take a look to the left of the block casting number, you might find a CON 2 (or something like it) and then a space with a letter and numbers. The con is conveyor # that moved the block at time of casting, the letter and numbers are month day and year. The example in the book is CON 2 F128. The breakdown is Conveyor #2 June 12 (probably 1988 because example had no timing gear oiler) Not exact, but should narrow down the possibilities some.

I suspect DKA is your engine suffix code. If so, I found two references and both say:

1979 - 250 CID - manual trans

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inline 6 ?

Thanks guys : that helps me a lot.