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Ryan, I know you already told me in a PM "Took us 16 hours on the CNC but we managed to take your block from 232 lbs down to 178.5 lbs. Keep in mind a stock 340 is around 162-165 lbs.... this is by far the lightest Tall deck R3 I've seen." But how much of that record lightness is from the large bore size? In other words if this was 4.00" bore what do think it would weigh?

Also, if you decked this block to minimum deck, which I think is 9.200" how much do you think it would take off? I was told you can take off #40 by max decking a block like this, but I am thinking more like #25. Maybe if it was cast for a 9.00 deck and machined to that height it would be #40 lighter than a tall deck.

Ron.



9.20's & 9.0 R3's used a seperate Casting from MP.

It's been a long time since I decked an R3 hard, I know we did one maybe 3 years ago & took around .300" for some reason, don't remember what it was for. Do remember we used a large shell mill on the CNC to knock the first .250" off & did the rest with the surfacing head to cut down time. You try to take .250" + off an iron block in an old Vulcan block surfacer & you can spend 2+ days doing one. CNC did it in hour & half? I have never really spent alot of time checking weight differences on decked blocks, but do recall doing a semi lighten job on a 9.0 block one time & it was around 185 lbs. Again, the deck on a 9.0 block is not much thinner than a 9.56 block since it is a dedicated casting..... Deck on a 9.56 is around .800" thick. You could deck one down around 9.20 no issues... & certainly that would remove good chunk of weight. You get into the shorter deck stuff & intake manifold availability is biggest issue for non W7/8/9 heads.

As for your bore question, 4.0" bore is pretty darn small, not many run that small, particularly in a Siamese block because cyl walls are so thick they can retain a ton of heat @ small bore. Most Siamese bores are ran @ 4.155" or bigger....however to answer your question.... Cylinder bores are 6" long on a tall deck SB Chrysler, & you'd be removing .105" all way around to take 4.0 to 4.21 like yours..... So that is basically very similar dimensionally to a cylinder bore sleeve... To be honest I have never weighed one, as I've never had a reason to?, but out of curiosity I will weigh a Melling sleeve this week & see what it weighs. That will be quick easy way to tell how much weight is removed in going from something in the "normal" 4.0-4.07 range up to 4.20+ bore.


Soo I have a question? When you remove all this extra casting do you induce stress into the block?
I know that some boring machines, when taking large amounts of metal, will do this Matt