My 66 GT had a 67 289 in it when I bought it so I've removed it and rebuilt an engine to be within the date code of what would have been original. I checked the exhaust manifolds off of the 67 engine and found one to be (at least appears to me) 5F28. My cars buck tag shows K28. Is that too big of a gap to be original to the car? The engine I'm putting in it has a build date of 5J28 so I'm trying to get the date codes within reason.
Thanks,
Allen