What is siamese bore

This is pretty much what you need tp know. Typically you can see this through the open freeze plug hole. V6 Brutal 6 Racing. Joined Sep 4, On all production 3. A production 4. All On center blocks no matter the bore size have a siamese casting. All Stage 1 3. The siamese bore 3. There were made at the point in the motorsports program where all 4 main caps were steel and they used a BBC rear seal rather than Buick. All 4. The pic posted by Captrob is indeed a siamese bore 3.

V6 said:. I hoped it made sense as I was writing it. Thats great Neal, Thanks for the info. Couple more questions if you have the time I've seen blocks referred to as Stage 1 and Stage 2 blocks I guess it depends on the oil pickup or drilled for the extra head bolts? Also, the coolant holes are different on some other pictures of blocks than mine. Where the 2 square shaped holes are on my above pictured block are, this other picture I've seen doesn't have holes there.

Different head cooling application? Same thing with the steam holes? Last edited: Dec 16, Stage 1 and Stage 2 3. The major differences between the Stage I and Stage 2 3. The 3. The square coolant passage in the deck surface is the give away when looking at pics.

I don't believe the difference in water passages serves any particular purpose the casting is just different. In a siamese bore block the casting arround the cylinder bores is attached between the bores. What are the strengths?? More strength added to the block. The FE engine is highly limited in it's displacement capabilities by the closeness of it's center to center spacing of it's bores. Even with a siamesesed block, you can only go so big on the bore before you run into the next cylinder, but with a siamese block you can take it to a larger bore because you have more added material to remove.

On an aluminum block, the iron cylinder sleaves are touching one another and encased in aluminum inside the block. What are the weaknesses?? Heated bore distortion is no greater with a siamesed bore then distortion from factory head bolts that don't reach to the bottom of the bores as in stock blocks, so that is a mute point. Why do you think they bore with torque plates?? So the stock block distorts more at 4 locations per cylinder rather than the possible one location on the outside cylinders, or the two locations on the inside two cylinders of a siamese bore block do from heat, Further still, alluminum conducts heat better than cast iron.

Back to top. OK Join. Joined: Jun 1, Messages: 3, Likes Received: Photoman Expand Collapse. Joined: Feb 3, Messages: Likes Received: 0. It just means there are no water passages between the cylinders. The SBC block is siamese. Not the best design but required with big bores in cylinder blocks that are smaller. Mike Expand Collapse. Gerry Expand Collapse. Old Rotor Flap Expand Collapse.

We used to use a block filler that I think was called TuffBlock or??