427 Block

[Snowboat]

I have a chance to buy a complete engine for $600. The casting number is 3963512. Can I tell if this is a four bolt block without opening it up? Will the presence of oil cooler holes above the filter be a reliable sign? Is it guaranteed to be a tall deck?

[Fiat48]

Only info I can find shows 2 or 4 bolt 427. I've never seen a 2 bolt tall deck. Far as I know, all were 4 bolt mains. To tell from the outside if it's a tall deck, look for the riser cast into the front of the block with an 1/8" pipe plug hole near the front where the intake manifold would seal.

[GofastRacer]

This is according to MorTec's list!..I would go by the cooler bosses to see if it's a 2 or 4 bolter but that's not a 100% accurate either since the bosses are on the the 2 bolt blocks and can be drilled and tapped very easily and someone could have done that at one time!....:rolleyes:
BTW, it is not a tall deck!...
3963512....427.......69......2 or 4 bolt
3963512....454.......70-76...2 or 4 bolt

[CircleJerk]

Snow, that 512 block is worth big $s to the chevy restorer. Place an ad in your local rag to trade for a later block plus money! That makes someone a 'numbers correct' muscle car. In case you didnt know. ;)

[Snowboat]

GoFast, how do you know its not a tall deck? I thought all truck blocks were tall decks. CJ, my local population does not support enough motorheads. I was going to save it for myself.

[Fiat48]

Tall deck
http://www.***boat.com/image_center/data/500/374Tall-med.JPG

[Snowboat]

That's the sure way, Fiat. I know that because the block you sold me had the same passage. Missed it on my build until I was priming the motor, never had a tall deck before. The engine runs great. Sometime soon I'll send you the particulars on what I did. Upgrading my rudder, rudder box, and the bottom now.
However, can I tell if its a tall deck from the casting numbers? I'm pretty sure that all I'll get from the guy is a casting number, some photos and a promise that it will rotate freely.

[Fiat48]

Gofast will have to tell you how he knows. Best I can figure out would be there was never a 454 tall deck. All were 366 & 427. The Riser is the dead giveaway. Never seen one without it. There was also a thin wall casting late model tall deck. It had a Big L cast into the side of the block. But it had the riser. I'll dig some more.
Update: all the info I can find shows it's a low deck 427 or 454 70'ish.

[GofastRacer]

Originally posted by Snowboat
GoFast, how do you know its not a tall deck? I thought all truck blocks were tall decks. CJ, my local population does not support enough motorheads. I was going to save it for myself.
Ken, a 512 block is not a"Truck Block"!. A truck block don't mean it came out of a pickup, they were used in commercial trucks, bobtails, tractors pulling 40' trailers etc. The reason for a tall deck was to add another ring for oil control because of severe duty use. Genuine "Truck Blocks" were 366-427, they never made a 454 in a truck block!. :)

[cheech]

most pass. blocks have very little space between the water pump mounting hole and the deck. a tall block has almost a half inch above holes,(.400)

[Snowboat]

Went to the library, to try to settle the difference of opinions. The Chevy Big Block Parts Interchange Manual, says they both have a 9.8" deck height. If its a four bolt, I'll get it anyway. Thanks.

[GofastRacer]

Standard block is 9.8, tall deck "Truck Block" is 10.2;)

[Cs19]

You need to understand that the blocks are different, a tall deck or truck block has a .400 taller deck height. Whatever you were reading was false.

[Snowboat]

What I am saying is........the casting number says it is a truck block, 9.8", and I'll have to hope on the tapped holes for the oil cooler. There are about ten other casting numbers for 366T and 427T. 3963512 is not tall.

[GofastRacer]

That's right the 512 is not a tall deck because it is not a "Truck Block". All the those casting numbers for the tall decks just mean the different years they were made, still the same block!..:)

[Cs19]

I just looked up the block and it says its NOT a truck or tall deck. Its a 454 or 427 STANDARD deck block. These blocks have the same bore.
So you read that its a truck block with a 9.8 deck? Where did you get this info from?
Are you assuming its a truck block because it came from a pick up?

[Snowboat]

The first info came from mortec.com.
3963512....427.......69......2 or 4 bolt
3963512....454.......70-76...2 or 4 bolt

[powerplay230]

Snowboat,-
Originally posted by Snowboat
GoFast, how do you know its not a tall deck? I thought all truck blocks were tall decks. CJ, my local population does not support enough motorheads. I was going to save it for myself. ------------
If those part numbers make it correct for someone's '69 or '70 restoration product it will be worth your while to sell and use that money to buy any block you want. The "gearheads" trying to make their resto' correct will pay lot's of money. Don't worry about the local population- Hemmingways, Ebay etc.... will suprise you. I have sold a few vintage pieces myself and suprised myself with the return, and have a buddy who has driven halfway across the country and paid thousands for a part that had the right tag/date on it for his '69 RS Z-28. Us boaters are used to selling parts for a fraction of what we pay, not more!!:eek: :eek!: :rolleyes: Sorry to waste your time if I misread that.
Rich