I have a Chevy six that came out of a 68 Chevelle wagon. The code on the block is F0403AN. Can anyone tell me if this is a 230 or a 250?
There used to be a link on here wher you could look up codes like this, but I can't find it.

I believe you need a different number.
This looks more like a date code.

Look under Casting #'s on the left

Will Willis

VStock:
Look on this page.

http://www.chevellestuff.net/1969/engine_id_codes.htm

Didn't see that code used in 68 so maybe a replacement engine? Worth noting the same code means a 194 in 1965.
Check casting date.
Hope this helps.

Thanks guys! That tells me what I wanted to know. I'll pull a spark plug to confirm it, though.