I found this number on my 460 heads when I removed the valve covers. At first I thought it may be a part # (meaning right or left) so I removed the other and found the same #. My question is what does this tell me about my heads?

 

its the date they were cast.

5 = 5th year of decade (probably 70's)
d = month which is April
16 - is 16th day of month.

so your heads were cast April 16th, 1975

the part number of the heads is found between the exaust ports on top of heads. probably D3VE heads.

rgds
Mike

 

Thanks for the info.

I was told these heads have the plumbing for an emissions pipe or something like that. I didn't think they started that until closer to the 80's?

 

if you mean the air injection pipe, then the 460 heads had them since 1970 at least maybe earlier. the DOVE heads i have from a 70 Lincoln had the ports in them.

all you need to do is tap them and install a plug.

rgds
Mike