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BBC Compresion Ratio ????

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Old Sep 16, 2008 | 04:17 PM
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Default BBC Compresion Ratio ????
I am building an iron head / iron block 496. I want to run it on 93 octane. How much compression is everyone running???
thanks
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Old Sep 16, 2008 | 09:49 PM
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don't go much over 10.5 comp. and you'll be fine.
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Old Sep 17, 2008 | 05:09 PM
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I had 10.5 in my aluminum headed 468 BBC and with a pump gas timining in it it still like the race gas a little more. keep it in the 10 range and don't go crazy with the timing.

My last car liked the Sunoco 94 the best and it was a stock internal LT1 with a 92 octane tune.
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Old Sep 17, 2008 | 05:33 PM
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No more than 10.0:1
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Old Sep 17, 2008 | 06:26 PM
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why can't you run higher compression in BBCs like you can in SBC's?
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Old Sep 17, 2008 | 07:52 PM
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they are much more sensitive to detonation from the extra fuel needed to run the larger displacement.
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Old Sep 18, 2008 | 06:26 PM
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c'mon go all out, my friend roger has a 14.5:1 compression on a 250 shot in his third gen
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Old Sep 18, 2008 | 09:05 PM
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my buddy in his 468 runs a 12.5:1 on pump gas with some extra additives. it pings a lil on the street but if he goes with 91 or better with a bottle of additives it runs perfect
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Old Sep 19, 2008 | 07:49 AM
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those octane boosters are terrible for carbs and injectors though. they leave residue that turns into a sticky wad like tar. tried that for a while too.
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Old Sep 19, 2008 | 07:59 PM
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thanks for the input i was trying to decide between 10.0 and 10.5 i know the iron head holds more heat and will detonate easier. I will proably keep it to 10.0 on 93 octane i dont like the octane boosters and i dont want to run race gas this car is going to be street/stip not a full race car
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Old Sep 20, 2008 | 12:55 PM
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Originally Posted by Fast93Z
c'mon go all out, my friend roger has a 14.5:1 compression on a 250 shot in his third gen
Ill be up in that range with a 300 shot but will jet it down most of the time so I don't hwave to worry about it.


Street car also.
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