Re: Siamese Bore R3's for Street Use
[Re: B3422W5]
#437831
08/14/09 04:47 PM
08/14/09 04:47 PM
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Joined: Dec 2006
Posts: 3,395
Pa
Hot 340
OP
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OP
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Quote:
I am pretty sure Chevy 400's were siamese bore, and they have logged hundreds of thousands of street miles  
Thanks Don, just read some stuff in Jim Szilagyi's book that said it should be done, but some of his other info made me question his techniques...a little outdated maybe.
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Re: Siamese Bore R3's for Street Use
[Re: Hot 340]
#437832
08/14/09 05:11 PM
08/14/09 05:11 PM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
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Lynchburg, VA
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Some blocks have been drilled between cylinders. You drill at an angle back to the water jacket. If you look a lot of the circle track heads had water passages drilled between cylinders. Most head gaskets have two small holes between cylinders this is where the hole starts and is angled about 45 degree towards the water jacket.
Simply because you are asking I would say do not do this. This mod is for someone who is fully aware of the problems they may cause and what bore they can get away with after doing this.
Leon
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: Siamese Bore R3's for Street Use
[Re: Leon441]
#437833
08/14/09 05:50 PM
08/14/09 05:50 PM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
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Oakland, MI
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Quote:
Simply because you are asking I would say do not do this. This mod is for someone who is fully aware of the problems they may cause and what bore they can get away with after doing this.
Leon
Maybe you could enlighten us all...?
As I understand it, the holes are not there to flow water> They are mainly just steam escape holes. The holes can be very small, and should not effect strength much at all. All low deck R3's I've seen already have this done. The only one's I've seen that don't have the steam holes are tall decks...
Mopar doesn't put any further bore limitations on a tall deck then they do a short deck?
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Re: Siamese Bore R3's for Street Use
[Re: dizuster]
#437835
08/15/09 10:11 AM
08/15/09 10:11 AM
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Joined: Feb 2005
Posts: 5,207
Menomonee Falls
DemonDust
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Menomonee Falls
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Quote:
Quote:
Simply because you are asking I would say do not do this. This mod is for someone who is fully aware of the problems they may cause and what bore they can get away with after doing this.
Leon
Maybe you could enlighten us all...?
As I understand it, the holes are not there to flow water> They are mainly just steam escape holes. The holes can be very small, and should not effect strength much at all. All low deck R3's I've seen already have this done. The only one's I've seen that don't have the steam holes are tall decks...
Mopar doesn't put any further bore limitations on a tall deck then they do a short deck?
The reason for the bore limit is because once the holes are drilled, you can't get the max bore out of the block anymore. You need to keep enough metal between the piston and steam jacket so you don't blow thru 
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Re: Siamese Bore R3's for Street Use
[Re: Hot 340]
#437836
08/15/09 05:37 PM
08/15/09 05:37 PM
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Anonymous
Unregistered
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Anonymous
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i drill the 3 lower holes. (most blocks already have the center hole between the middle cylinders drilled) as well as the heads. just like a chevy 400.
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Re: Siamese Bore R3's for Street Use
[Re: DemonDust]
#437837
08/16/09 07:13 AM
08/16/09 07:13 AM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
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Oakland, MI
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Quote:
The reason for the bore limit is because once the holes are drilled, you can't get the max bore out of the block anymore. You need to keep enough metal between the piston and steam jacket so you don't blow thru
Obviously if you drill a big hole in the wrong spot it can cause weakness issues. But done properly, I don't see how it can hurt much unless you're really trying to get every .001" of bore you can out of it.
Like I said short deck R3 blocks already have steam holes right from Mopar. Tall deck R3's do not. But Mopar doesn't put any different bore limitations on either...
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Re: Siamese Bore R3's for Street Use
[Re: DemonDust]
#437839
08/16/09 11:02 AM
08/16/09 11:02 AM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
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Lynchburg, VA
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Here is a pic of my old 9.600" deck R3 bored 4.245". There would have been no issue with steam holes at this bore as they start from a 4 O'clock position and are angled 45 degrees from the deck surface entering the water jacket.
The issue with this block if had had steam holes "may" have been when repairing the block with sleeves. This block had two next to each other on #6 and #8 that worked well.
Leon
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: Siamese Bore R3's for Street Use
[Re: Leon441]
#437840
08/16/09 11:05 AM
08/16/09 11:05 AM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
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Lynchburg, VA
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This is a pic of my 358WC R3 9.00" deck block. This block has a 4.200" bore. The pic is not that good but the steam holes are there between all cylinders.
Last edited by Leon441; 08/16/09 11:13 AM.
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: Siamese Bore R3's for Street Use
[Re: Leon441]
#437841
08/16/09 11:12 AM
08/16/09 11:12 AM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
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Lynchburg, VA
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Here is a pic of a stock block 69' 340 that was done before there were better blocks. It is sleeved and 3/4 filled bored 4.125". No steam holes and driven on the street when it was 4.100" bore.
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: Siamese Bore R3's for Street Use
[Re: Leon441]
#437842
08/16/09 03:37 PM
08/16/09 03:37 PM
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Joined: Feb 2003
Posts: 885
south louisiana
lowell66dart
super stock
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super stock
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Posts: 885
south louisiana
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That book about building big inch smallblocks that came out a few years ago has some info about drilling siamese R3 blocks.
2021 Dodge 2500 4WD Cummins
2020 Challenger R/T Scat Widebody
2007 Charger R/T 5.7
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