what does that mean exactly?

 

I believe it means that the cylinders are actually connected together with metal. Meaning that there are no water passages between the cylinders.

 

ooo
whats the advantage to this?

 

the Small Block 400 was a advantage

Im pretty sure that if they had passages then that would compensate strength of the cylinder walls. Thats why 400's are referred to as siamese 400's. Or so I heard ....

 

No real mechanical advantages, other than it is the only way to get a 4.125" bore in a cylinder case that has 4½" bore centers and still have a reasonably thick cylinder wall (one that you can't see through).

 

thats sort of what i figured afta they stated that there were no water passages. just was wating for someone to confirm. thanks alot

 

And while there are no true passages (routes that flow completely through), there ARE steaam holes drilled between the cylinder bores to admit coolant, then allow it to flash off into steam to remove heat from that area. Theoretically, the coolant percolates in that area like in a coffee pot (Did someone say "coffee"? Where?)

I'm not sure if it's the "hot" trick any more, but in addition to enlarging the steam holes on a rebuild, some engines have been cross-drilled, tapped, and plugged on the outer side of the case to allow coolant to truly flow through the area. I'm not sure if there is any advantage to this, but 400 SBCs have been know to have some weakness in the bottom areas of the castings already, so the practice may be "taboo" these days. 400 cases are getting harder to find, you know.

 

some of the blocks you can order from gm are like this. jus wondering what it meant

 

In most engines, the cylinders are individual sleeves that the block is cast around. You can see space between them. In the 400, all 4 cyls on each side are one big assembly, with no space at all between them.

Alot of the performance blocks are made that way, mostly to allow for the largest possible overbore. It also adds strength to the block, because when made that way there's a big chunk of steel holding itself together, instead of 4 little pieces suspended in the cast iron.

I've had alot of 400s over the years, never have had any cooling problems with them personally. I have no clue why people thingk they're hard to keep cool; they have no problems at all when equipped with a properly sized and maintained cooling system, i.e. stock, unmolested, V8, correctly working. The stock cooling system in my 83 car seems entirely adequate for the 400 that has spent about 12 years in it off and on so far.

 

People were overheating them because they were using 350 heads that have no steam holes drilled in them, rendering the whole idea useless. That's pretty much how the bad rep for siamesed blocks started.

 

how bout the disadvantages.... unevent heating and cooling.... isnt that the reason why 400 blocks are more prone to cracks than 350s

 

i thought there problem was the rod/stroke and it made for premature cylinder wear. im not sure. please correct me.

 

Here is a picture of siamese 400's. Like said earlier if you drill the steam hole in the heads you will not have a problem. plus this little bugger can make plent of easy horsepower, with limited stress on the engine. I have one that im in the process of building and plan on getting close to 500 hp/tq.

 

Negative, the question about the rod/stoke was due to the use of 5.56 stock rods, however the reason Chevy had to use the shorter rods because they increase the stroke to 3.750.
If doing a rebild its beneficial to use the longest rod that your budget can support 5.7 or 6.0.