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