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BBC Bowtie block cylinder bore limits
Posted: Tue Dec 29, 2009 10:33 am
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
Posted: Tue Dec 29, 2009 1:27 pm
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.
Posted: Thu Dec 31, 2009 3:57 pm
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 !
Posted: Fri Jan 01, 2010 12:54 am
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?
Posted: Fri Jan 01, 2010 6:02 pm
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
Posted: Mon Jan 04, 2010 5:20 pm
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 !
Posted: Tue Jan 05, 2010 1:22 pm
by Wannabe
You gotta love this WizBang guy!
Posted: Tue Jan 05, 2010 5:40 pm
by wizbang
Gees, when I grow up , I Wannabe going faster !!!!!!
Posted: Tue Jan 05, 2010 8:54 pm
by speeedr
Define < prominet builder > ? does he write for hot boat magazine maybe ?
Posted: Wed Jan 06, 2010 2:16 am
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.
Posted: Wed Jan 06, 2010 1:24 pm
by Wannabe
speeedr wrote:Define < prominet builder > ? does he write for hot boat magazine maybe ?
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.)