[blownb310]

I've just spent about 1.5 hrs searching for the answer to this question, so please bear with me if this has been asked before. I would like to identify a service replacement shortblock that I have. I was told it is a 400, but it has the valve relief scallops down lower in the deck [top of bores] like the '66 and earlier engines did. The numbers on the block are SR83414, then there is one other number on the front of the block but the first digit is hard to make out. It's either 36138 or 86138. The casting date on the rear next to the dist is L076. It's of course, 2 bolt main. What do I have here please?

[Shadowjack]

Find the block casting number anywhere? Mostly behind the right cylinder bank, starts with either 9, 4, or 5. Get that and we'll tell you what it is.

[blownb310]

Originally Posted by Shadowjack

Find the block casting number anywhere? Mostly behind the right cylinder bank, starts with either 9, 4, or 5. Get that and we'll tell you what it is.

Thanks shadowjack,

I know exactly where you are referring to, as my '69 and '70 blocks have them there, but this engine does not have any raised numbers cast into the block there at all.



Just the raised 36138 just to the right of the distributor. The casting date L076 is seen there too.



The only other numbers I can find are up front:



There are no numbers in the lifter valley or on the outside of the block near the three core plugs on either side.

Thanks,

Mike

[pontorquer]

Hi ! You have a 1967 Pontiac 400 SR block, rare find ! Block code 9786133.

[blownb310]

Originally Posted by pontorquer

Hi ! You have a 1967 Pontiac 400 SR block, rare find ! Block code 9786133.

Thanks pontorquer,
I appreciate the identification! I am curious how you figured that out. Was it through the 36138 near the distributor? What reference material did you find it in?

Thank you,

Mike

[goatasaurus rex]

my '73 SR has a block casing #.FWIW

[Shadowjack]

He and many others of us know that 9s, 8s, 6s, 3s, and 0s are hard to tell apart, and that a '67 400 block has the casting number 9786133. No others come close. The oil passage plug is drilled through the number, which is why they were moved to the right cylinder bank.
Year One catalogs used to have this info.

[blownb310]

Originally Posted by Shadowjack

He and many others of us know that 9s, 8s, 6s, 3s, and 0s are hard to tell apart, and that a '67 400 block has the casting number 9786133. No others come close. The oil passage plug is drilled through the number, which is why they were moved to the right cylinder bank.
Year One catalogs used to have this info.

Thanks Shadowjack,

Now I understand.

Does anyone know why the valve relief "eyebrows" are located lower in the bore centerline for the '66 and earlier heads?

[pontorquer]

pre-68 block used to put the casting #'s by the distributor hole and on side of the block like that 66 421 I had then 68 and up moved it to the right passenger top side of block, under where the head bolts on. Where you tought it should be. Regards, Pontorquer ie. PONTIAC = TORQUE MONSTER !!

[Shadowjack]

In '67, the valves were moved closer to the centerline of the heads, so the chamfer is different.

[blownb310]

Originally Posted by Shadowjack

In '67, the valves were moved closer to the centerline of the heads, so the chamfer is different.

Thanks Shadowjack,

Yes I realize that, but I guess what I am trying to verify is that this engine must have been intended for a replacement in a '66 vehicle then right? Or maybe some early production '67's came with the left over '66 heads? Can anyone shed some light on this?

[Shadowjack]

Not sure what your question is. The valve relief eyebrows (in the pistons, which is not what I thought you were asking), are different between '66-back and '67-up for the same reason the cylinder chamfers are different. This is a '67 model year block, (cast December 7, 1966) so it will have '67 chamfers and presumably corresponding pistons.

[blownb310]

Thanks again for the reply Shadowjack,

I didn't mean to confuse you. From my original post:

Originally Posted by blownb310

I was told it is a 400, but it has the valve relief scallops down lower in the deck [top of bores] like the '66 and earlier engines did.

That's just it, although this block was cast in '67, the upper cylinder scallops are where they should be for a '66 and down engine. I guess it makes sense because if you have a '66 car under warranty and you need a replacement shortblock the following year, you would need one with the earlier valve centerline scallops to match your original '66 heads. In this scenario, you'd be getting 11 more cubes [a 400 in place of your 389] as a result of the warranty work. Has anyone ever heard of this before?

[Shadowjack]

'67s still had those scallops, although they were in a slightly different place compared to the '66s. I don't recall when they quit cutting them.