[johnsma22]

The block casting number of 481988 means that it is a 1971- early 1975 400 block. The numbers you gave from near the distributor are unusable as a date code, as it should have a letter, followed by 3 numbers. The letter = month, next 2 numbers=day of the month, and last number=last digit of the year. For example, A273 would be Jan 27th 1973 or 1963. From what I could find though, there is only one YN coded 400 block with the casting number of 481988.

It is a 1973 230 hp 400ci that originally came in an automatic B or G body with 8.0:1 CR, an 066 cam, 4 barrel with 4X(7H) heads.

Head drivers side J088: This date code could mean Oct 8th 1968 or 1978
Head Passenger side B049: This date code could mean Feb 4th 1969 or 1979

The head date codes don't really tell us much with out the casting numbers located on the center two exhaust ports on both heads. Suffice it to say that they are not originals to the block and by the difference in date codes are most likely not even a matched set, even if they are the same casting code.

So what we really need to continue is to try and get the date code near the distributor to confirm the year of the block, and the casting codes from the center two exhaust ports on the heads. If the 400 block you have is from 1973 and is in good condition ie.. not cracked, etc, it would be a good candidate for a rebuild.

I included this link to a site that has great info with photos to locate where to look for all the right numbers.


http://www.yearone.com/updatedsingle...pontengid1.asp

John