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Discussion Starter · #1 ·
been looking at carbs and was recomended 080576S from holley tech line

these carbs are $700+ a piece is there an alternative?

496 10-12psi max

steel crank dual key ways
steel h beam rods

8.25 to 1 compression

6500-7000 max rpm

aviation gas or should I go E85????
 

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been looking at carbs and was recomended 080576S from holley tech line

these carbs are $700+ a piece is there an alternative?

496 10-12psi max

steel crank dual key ways
steel h beam rods

8.25 to 1 compression

6500-7000 max rpm

aviation gas or should I go E85????
I just run a regular HP style carb, and tune it unles it is a blow through. If you have a blow through setup I would get a custom carb from quick fuel, csi, carb shop etc. As for the gas E85 is a good choice, but you really need to keep an eye on it with a AFR gauge. It can be really inconsistant.
 

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the major thing I see with them is that they boost reference the power valve circut, which you can do to any 4150, requires blocking off the power valve vacume port in the base plate, making a groove to another port and use the side port run to the intake below the blower to signal the power valve...other than that just jetting..Rob
 

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been looking at carbs and was recomended 080576S from holley tech line

these carbs are $700+ a piece is there an alternative?

496 10-12psi max

steel crank dual key ways
steel h beam rods

8.25 to 1 compression

6500-7000 max rpm

aviation gas or should I go E85????
Doug..if i remember correctly,are you not running the 250 cid blower?Grabbing 10-12 lbs of boost over 496 cid will be a challenge.The smaller roots type blower works great with a static 9/1 cr at lower rpm.imho,a 496 spinning to 6500 requires an 8-71 at 436 cid per revolution.
I am sure you have done your homework..and under the hood stealth has to be the reason to stick with the smaller lung.OK by me.
As for the expensive dual holley blower specific carbs.I stayed away from them.I wrangled up a pair of 850 dp,s..boost referanced the primarys and blocked off the secondary pv and upped up 10 #.s.Pump size and cams/acc nozzles/booster local are some sc mods that you can do yourself for savings.If you go e85..you will need a carb that meters a ton of fuel..like an alky carb.Your combo should be able to eat 93 pump swill if you keep your effective cr with boost under 12/1 and a conservative tune.
 

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Discussion Starter · #6 ·
Doug..if i remember correctly,are you not running the 250 cid blower?Grabbing 10-12 lbs of boost over 496 cid will be a challenge.The smaller roots type blower works great with a static 9/1 cr at lower rpm.imho,a 496 spinning to 6500 requires an 8-71 at 436 cid per revolution.
I am sure you have done your homework..and under the hood stealth has to be the reason to stick with the smaller lung.OK by me.
As for the expensive dual holley blower specific carbs.I stayed away from them.I wrangled up a pair of 850 dp,s..boost referanced the primarys and blocked off the secondary pv and upped up 10 #.s.Pump size and cams/acc nozzles/booster local are some sc mods that you can do yourself for savings.If you go e85..you will need a carb that meters a ton of fuel..like an alky carb.Your combo should be able to eat 93 pump swill if you keep your effective cr with boost under 12/1 and a conservative tune.
George, you are right, stealth mode and has to be under the hood, if I had a two car garage I wouldn't have thought twice about 8-71, I spoke to Holley/Weiand tech line several times before the purchase and did alot of research on this blower and it is capable of over 12lbs of boost, my brother didn't want to believe it either but it is, the only difference is that I need to spin the blower 2 to 1 which will heat up the air inlet temps which is why I am heavily considering E85, there is another thread i started called anyone running E85 and got a response from a really nice guy who linked me up with another really nice guy who schooled me yesterday on the E85, its 105 octane and nothing needs to be changed other than the carb and maybe another inline pump which isn't a big deal, the smaller blowers actually are better at creating low end boost compared to its big brother 6-71/8-71, these blowers do not need to be overdriven as much to create the same amount of boost, I am at work right now but I do have the data on how much boot this lil blower can make and be safe, this lil blower can safely be spun to 14000 rpms or two time my max rpm wich is 6500-7000. At $2.75 a gallon I am seriously thinking about using it, problem is my engine builder is in California and doesn't have much if any access to E85 and its being dynoed there, I may have to ship him out 10 gallons or so if thats possible? Remember I only drive the car a dozen times a year if that so street manners and gas mileage are not a concern of mine. I want a wild pro street setup and I am right on track with the solid roller and e85 combo with the blower. I am looking at two new pro form 750dp setup for a blower and e85 $675 a piece. Im looking to make 750+hp and wouldn't be surprised if it makes closer to 800hp with e85 and with e85 it will act as a natural inter cooler and let me run closer to 9 to 1 compression. Everything is still in the works and nothing is set in stone yet so Im doing my homework. thanks for your help any suggestions are appreciated
Doug
 

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Doug..I see no issues with you overdriving the 250 blower with e85 calibrated carbs.The cool alcohol will increase your adiabatic effenciency and like you stated..act as a chemical intercooler.Boy oh Boy..this e85 might just be the hot ticket..especially for the forced induction crowd.Your like me,short blasts in the hot rod on weekends,so cost of fuel is a non issue.If you can make 12 lbs of boost over 496 cid with a 250 at 2-1 and not overheat the incoming charge with e85..I say you have a winning combo.I opted for the 8-71(non stealth) over 460 cid with 94 pump swill.I would wager that both our torque curves are flat right out of the gate.Your e85 is cheaper by the gallon than my 94..but will require more of it to go the same distance.FWIW..who cares,we bolt on roots blowers over big blocks for obvious reasons.
 

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I would PM norvalwilhelm. As I recall, he had his blown BB running very good with some wide band tuning. Copying his setup would be a good place to start.
 

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Discussion Starter · #11 ·
been talkig with Shawn Mendenhall and he gave me the go on the e85 and said ill be bale to run more compression wich will help part throttle driving around town

the carbs will be pro comp 750dp for use with e85 $675 a piece :confused:

i need to talk to aeromotive to see if my current fuel pump will flow enough fuel to power 800+hp with e85, i just hope someone over there knows something about the stuff

if anyone knows about my pump please let me know if i need to add another pump, im thinking i should to be on the safe side of the fence
 

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I would be really suprised if you can get 12 pounds of boost out of a 250ci blower on a 496 engine.

I could not get more than 10 lbs of boost out of a 162ci blower on a 350ci, and even then it didnt make any more power than 8 pounds of boost because of the heated charge.
 

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Discussion Starter · #13 ·
I would be really suprised if you can get 12 pounds of boost out of a 250ci blower on a 496 engine.

I could not get more than 10 lbs of boost out of a 162ci blower on a 350ci, and even then it didnt make any more power than 8 pounds of boost because of the heated charge.

please read the pdf i am listing, nobody wants to believe this, I did my homeowrk on this blower and it is very capable of pulling 10+psi out if it, i spoke to holley tech several times and yes it is capable of doing, i will need to overdrive it 2 to 1 wich it is capable of doing and doing it safely and under the 15000 rpm max limit for the blower when its dynoed i will let you all know what it does please read the pdf i am listing a link for and this will be fed by E85 fuel wich is very different than the regular fuels you have used, dont take this the wrong way im not going against you but i spoke to several people before buying this blower and it needs to stay hidden under my 4" cowl if it wont ill find a 5" to replace my not so fun lift off hood

Read page 10, thanks for any advice on the blower, this is my first roots blower
http://www.holley.com/data/TechServi...ech%20Info.pdf
 
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