BBC Bowtie block cylinder bore limits

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s/c 266
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BBC Bowtie block cylinder bore limits

Post by s/c 266 »

My 9.80 Mk 4 BBC bore is 4.565 now.
Casting 10051107
Part number 10051106
274#

Anyone know if this will go to 4.600 without grouting? 15:1 drag race engine

Thanks
Paul
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Post by Wannabe »

I am really not certain why, but GM is very mild when they put in print what their blocks are capable of in the way of max bore. They say that the bowties are only good to 4.560 and I have two in my shop by 'very prominant builders' that are both over 4.610 and not filled.
Then when compared to the dart and merlin (not pro) that advertise 4.625, the Bowtie and CNC Bowtie have very similar wall thickness.
Then they say that their DRCE I blocks are only good to 4.600. Please show me a pro stock runner that had a bore in these blocks even close to that.
I don't want to say "Sure" because I don't know the history of your particular block, the options, etc. But I am doing a circle boat engine right now with that block that will be 4.615.
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Post by wizbang »

I have the same casting at 4.625 and it is 16.2:1 , injected alcohol,,, no problems since 2000 when we put it together !
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Post by s/c 266 »

wizbang wrote:I have the same casting at 4.625 and it is 16.2:1 , injected alcohol,,, no problems since 2000 when we put it together !
is it still a 100% water block?
Paul
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Post by PWMAX »

I am doing one now, working with existing parts. Its at 4.625. Its block filled to bottom of water pump though.

Frank
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Post by wizbang »

I can't fill mine as it is used in a circle boat. I built this engine in 1999. It is still kickin ass today !
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Post by Wannabe »

You gotta love this WizBang guy!
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Post by wizbang »

Gees, when I grow up , I Wannabe going faster !!!!!!
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Post by speeedr »

Define < prominet builder > ? does he write for hot boat magazine maybe ? :twisted:
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Post by mudracer »

I have this same block.

Aside from the above sarcasm, has anyone had issues with this block being bored to 4.625? my block is at 4.530 now, needs to go 4.560, and I am trying to make sure i can update in the future if necessary.


If it will go to 4.625, i will be satisfied. If i have to fill, its not a problem, but i would like to know the limit before i ruin it by not filling it.
Duane


http://sutherlinbbfest.org/
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Post by Wannabe »

speeedr wrote:Define < prominet builder > ? does he write for hot boat magazine maybe ? :twisted:
Ouch!
No, I meant prominent when I said it.

In answers to your question, those Bowties will be fine at 4.560 and beyond. I like them every bit as much as the Darts and Merlin II and III for strength. (As long as the block has not been totally hammered or really screwed up in the past. There is always that concern.)
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