[tom s]

A friend has this block and it has a couple threaded post cast into the lifter area.Any clue what for?Tom

[Scott Stoneburg]

Check out all the lifter bore braces. Is that a RA-V block?

[misterp266]

Early block? Looks like some sort of pressure ports at the oil feeds to the deck.

[7T2]

looks like 1/8" npt threads-
oil line taps for external oiling of springs for nascar maybe?
pic looks to show bosses cast up each side of the lifter valley @ those locations
is this a SR block?

[tom s]

Its a V block like I have never seen.Tom

[shermanator2]

That block looks to be cast for rocker oiling through the studs like '64 and earlier. Like others noticed, those might be pipe threaded oil ports. Is it a SD421 block?. Tom, are you just trying to get us all excited?

[tom s]

I have owned a lot of V blocks,none like this.The bosses are 2in deep and fine thread.Tom

[242177P]

I'm thinking it's the missing link between the NASCAR era SD, and the RA V? Like a super-early V??

[sdbob]

I've seen at least 4 SD455 blocks and one machined for cam driven oil. Nothing like that.

[steve25]

Those kind of rectangular forms cast into the lift valley walls speaks SD 455 to me, although those bolt bosses are not production SD455.

If the block casting number has a D in front of it then it’s for sure a engineering development SD block I would have to say, or maybe a iron block version of what would have been the Hemi as that set up did not use a valley pan, no, so maybe that was where additional bolts pads where added to bolt the intake on.

What size are the mains?
What’s the casting date?
How many motor mount bolt holes on each side?

[shermanator2]

Originally Posted by 242177P

I'm thinking it's the missing link between the NASCAR era SD, and the RA V? Like a super-early V??

The casting provision for the oil gallery to the head says it must be 50's or early '60s. They stopped using those in '65, but I am not sure how long they left the casting that way. In a regular '69 400 block it is not there I know.

The webbing across the lifter bores implies a heavy duty special race block.

So Tom, those threaded holes are not drilled into oil galleries? Seem like a coincidence that those bosses would be right on top of the vestigial oil galleries.

Date code on the block?

Could it be something like a late '50s GMC truck block. Maybe they did something different.

Fun mystery.

[PontiacJim1959]

Being fine thread, I don't think they would be for any type of oil line or oiling system.

However, those may have been bolt attachments for what was going to be a set of roller lifters held in place by a stamped type valley pan as shown in the photo. Has the look of the 1996-2002 Chevy set-up, except it is one piece.

[tom s]

First of all its a 69 block!No D or DS number.Large dizzy hole.Keep guessing.I know what it is,never owned one or seen one in person.A hemi block would need deep grooves cast into the deck of the block to clear the push rods.Tom

[mgarblik]

OK, as long as we are guessing I will throw a real wild one out there. They are for oil feeds for the overhead cam V-8 engine that really never happened. Would that be rare or what? Have you been able to verify oil goes through them? A more likely reason for the holes is a cleanout for chip removal when drilling that long passage for oil up to the deck. What it was for from there is a mystery. Can't imagine they would have gone back to stud oiling in 1969.

[tom s]

The block was designed in 1968 for a special purpose.Tom

[Tom Vaught]

Block has one of a kind, pushrod Valley "walls" I have never seen another block with that
wall shape contour. Lots of blocks with dashes, smooth, small ribs, but that casting is for sure unique.

H. B. Bailey many years ago (NASCAR PONTIAC GUY) had a couple of blocks done by Tom Nell that looked somewhat like that block. They were the first blocks I have seen with the full ribbing like the 455 SD Engines.
What is the main bearing journal size of the block Tom?

Tom V.

[Joe's Garage]

I believe those are oil passages above each boss that head up towards the deck.

I'm thinking some sort of experimental dry sump system to oil the lifters/valve springs/top-end.

Screaming NASCAR to me. But what do I know - I was only 11.

I'll just put in a formal request for PLENTY of adequate photos of ALL areas of the block (top, bottom, front, back, insides), once you let us all in on the secret. Pretty please.

Thank you.

[tom s]

OK,was designed for Arni when he was running the blown RA V,it a 428 angle main block.Still not sure what those bosses were for,maybe someone close to Arni will ask IF he remembers.Im told he was only getting 10 runs on the original Hi nickle 421 SD blocks and this block would fail about the 25-30th run.50 plus years ago.NOTHING I posted is forsure.Tom

[johnta1]

Does it have a block casting number of 9792968?

[Gary H]

I say it's for the Trans Am racing circuit like Jerry Titus ran in. Additional oiling for bosses for external oil pump?