Block Casting ID

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Sep 26, 2004 | 06:18 PM

'78 Custom

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From: Griffin. GA

Block Casting ID

Everyone here is probably tired of me asking questions, but here it goes anyway. I have seen a lot about looking up block casting #'s and such, where is this # on the block and where can you look it up?

Sep 26, 2004 | 11:53 PM

63redtudor

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Look beneith the exhaust manifold along the oil pan line & it should be there. All 240/300s I've seen have the number there anyway. As for differences in the blocks (I take it thats why you want to know the casting #s?), there aren't many at all. The early 240/300 blocks usually have differet casting numbers (240s usually have the casting letter that indicates a full size car), but other than that are identical. The 240 heads are different from the 300s (higher compression) though. Up though about '83 or so you won't find much of a difference between the blocks other than the casting numbers. The '83-4 blocks added a oil dipstick mounting point on the block behind the oil filter for 4X4 aplications. Earlier blocks used a location in front of the distributor (2WD) or a dipstick that goes through the pan (4X4). The next big change was when the EFI 300 came out (late '86), the mechanical fuel pump hole was eliminated (the mounting point & bolt holes are still there as is the cam lobe). The EFI heads are quite different, but the block itself didn't change much. I'm sure you may find other minor changes, but these are the major ones that I know of.