993 or 487x Cast Iron Head MYSTERY.....????
I recently purchased a set of what i think are 993 heads. I took them to the machine shop and had them cleaned and checked out. When i went to pick them up the machinest said i had 487x heads.
So here is the mystery.....on top of the head the casting says xxxx993 but on the bottom inside closet to the intake there its cast with 487x the machinest says you go by the bottom number. the casting dates are between jan 72 and may 72.
So whats the real deal here ????
Last edited by 3dinter; 12-05-2011 at 11:25 AM.
I can't say for sure which is the "real" number, but I will say I have a set of heads that read 598 on top and 441 on bottom. I don't think it really matters though since 441,487,487X,993 are all relatively the same. Just for ease of teching, make sure the number on top is legal as that is the one most tech guys check if you have head number rules.
it could be recast to repair damage, Dover cylinder head and bryzinski i believe can both recast factory heads.
I tried to post some pics this past weekend, but it wouldnt let me,ill keep trying to post them.
Originally Posted by carowner73
Ive been told that when the heads were cast at the foundery that there is a top and a bottom to the casting box and somtimes they would use a mis match set and thats how this happens .I don't know if this is true but have had sevral sets that the top and bottom numbers don't match . This might be bull crap i dont know . My question is if this is true where is flow difference in the port runner or bowl area of the heads ?
Good thought, i have seen how they cast items with the 2 sides or top and bottom...so it sounds legit and makes sense.
Originally Posted by sneak
I have a set that has 493 on top and 487x on bottom.
i have 2 sets one has 993 on top and 487x inside a water port and another set that has 993 on top and 487 under the intake port on bottom side of the head
I have seen plenty of heads with miss matched numbers, your fine though.
pretty much the same head.
Will port and polish for cash
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