So i'm in the process of buying a used 351w to put into my 65 fastback and have found what is presumably a pre-74 351w. I've got the casting numbers but i'm not finding the right info on the web, a lot of contradictions between various sites. Here's what i've got as it appears on the engine:
4J12
D4AE(6 or 8)015AA7
so what year engine is this? i'm told that 4j12 means it's from 72, but i'd be a fool to believe the guy selling it to me lol

-kirk

EDIT: i should add he says it's from a 72 mustang coupe, could this be a 351c? i've found the data on this, after 71 all 351s were 351c's not 351w's. confirm?

 

D4AE lines up with a 351w casting number, but it means the block was made in the late 70s, not pre-74. Likely 76 or 78 (depending on the last number). This means it's set up for emissions (smog ports and such).

I have no idea what 4j12 means...

 

D is for the decade 1970 and 4 is for the year...The block could have been cast later than this but not earlier like JoJo said...That is why we need the date code..In this case 4J12....The first number is the year of the decade..The second letter is the month of the year and the last number is the day of the month..You have to figure out what decade but since the other code was D4AE we know it was cast in the 70s...So it breaks down as being cast in 1974 Sept 12..

 

i saw the same information online, however he claimed it's pre-74 which the casting number agrees with if it were a 351c (same numbers exist for 351c and 351w...). and it was out of a 72 coupe which implies a 351c. I haven't seen the engine in person, just spoken with the guy over the phone several times. I think this is bust, probably a 351c not a 351w. I'd guess it's an honest mistake, i never detected an attempt to mislead
i've found out in text just now the guy never knew there was a different between a 351c and 351w.... i've been asking him this stuff the whole time... oh well, just as well. Anyone here care to sell me a '74 or earlier 351? lol

-kirk

 

just curious, why so set on pre-74? Only reason I'm asking is because I'm looking for a 351w as well and I've found one in a 87 f-150. Although I'm only looking to use the block.

 

well at the risk of creating a bit more competition in finding a pre-74 i'll tell you... lol
a 351w block made in or prior to 1974 is a heavier casting, and thus a stronger block. If you're looking to really tune up the engine (stroking and boring) it's beneficial to have that extra bit of cast iron. Since i'm in no hurry to get a 351 i'm willing to wait on the right block. my 302 is gorgeous right now, but i have horsepower plans

-kirk

 

since i already have this thread it seems appropriate to ask. Does it matter if i get a 69-71 or a 71-74 in terms of mounting the engine? I have a fiberglass Shelby hood with a steel frame, I'd like to keep it that way

-kirk