ivan
Junior Member
Posts: 52
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Post by ivan on Nov 20, 2009 7:31:52 GMT -5
what would be a good compression ratio for blown big block alky around 15-18 lbs could i run around 10.1?
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Post by jgruzen on Nov 20, 2009 8:32:01 GMT -5
I'd kick it up a bit...SBC's are happy around 10.6 - 9...BBC can be run at 12+ and not worry about hurting stuff..
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ivan
Junior Member
Posts: 52
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Post by ivan on Nov 20, 2009 12:12:24 GMT -5
I am running open chamber heads can i get that compression .
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Post by bobbycottrell on Nov 20, 2009 18:50:40 GMT -5
It depends on what you want to do with the car it will work at that compression just turn the boost up but I have 11.8 with 11 lbs it runs right around 203mph BUT if you are up in the higher compression ratios you definitley have to have a stout bottom end and a cylinder head with a descent deck thickness thats whats going to make it live.
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ivan
Junior Member
Posts: 52
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Post by ivan on Nov 21, 2009 18:54:09 GMT -5
I was wanting to run around 10.5-1 . block is 2 bolt main will have good crank .heads are aluminum ovals 119 cc will be in a bantam altered 108 " wheel base . right now we are running 9.09 @151 smallblock hyper pistons solid cam camel hump heads @ 7 lbs boost on gas and carbs. any suggestion appreciated never ran big block before plan on a solid cam for now . how hard will it be to get around 700 hp thanks
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Post by Jeff Smith on Nov 21, 2009 22:22:10 GMT -5
Depending on your cubic inch.. we ran a 468 at 11.5-1 with a comp .630 lift flat tappet cam with a set of merlin closed chamber heads and ran 7.50's all day long with a 6-71 at 32% over at Palmdale (usually 5000 feet or more) but it was a bowtie block. If you want to run an 8.60 index it's better to do it unblown. It's not worth the hassle for all the extra crap you gotta have to have a blower. you will make 700 horse easy on injected alky with a 13.5-1 compression ratio with a 468. If you want to run a 427... just add a little nitro.
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Post by tdracing on Nov 21, 2009 22:50:09 GMT -5
We ran a 468 BBC in our old NE-1 car, Iron oval port heads, big valves, chevy steel crank, Alum rods, roller cam. I ran open chamber head with closed chamber piston for 11 to 1 CR. Motor on alcohol made 875 HP and ran 7.50 with no problem.
Key to making it live is 4 bolt mains and good rods. It is the simple way to run NE-1, SB need a keener guy than me. ;D
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Post by chiefcabioch on Jun 14, 2010 22:45:52 GMT -5
why are you limiting boost ?, and I would stick with 11.5 it's a good place to begin
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