Dual 850 double pumpers?

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UDUST81

UDUST81

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just been looking into a lot of tunnel ram builds recently and have noticed a lot of people run dual 750 double pumpers or dual dominators, but i never tend to see dual 850s... any reason for this? just honestly has me curious
 
Most of the tunnel ram carbs that are built for serious race engines flow much more then advertised cfm. My carbs are 750 based but with the aftermarket main bodies they flow much more.
 
i guess im really just asking why does it seem whenever someone feels they need upgrade past 750s they seem to always just jump up to dominators, i just found it odd no one seems to use 850 based carbs
 
Its alway going to draw only what it can. 2 750's dont equal 1500 CFM draw because the drop in vacuum they create when they open. Read Vizard's "super tuning" book.
 
pishta said:
Its alway going to draw only what it can. 2 750's dont equal 1500 CFM draw because the drop in vacuum they create when they open. Read Vizard's "super tuning" book.
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Ding ding ding! Wait till you see my tunnel ram setup blow everybody's mind! It can't make power below 5k rpm! It can't run on the street! It's gonna cough and sputter and puke! Hahahaha I can't freaking wait!
 
Not at all, Plenty of happy street dual quads. Some stress on overcarburetion but the math doesnt compute if they add the 2 CFM's together. For instance, the triple deuce six pack was 'supposed' to flow like 1350 cfm but it actually flowed closer to 780 cfm on a 440 just because the pressure drop across 6 open bbls is alot less than across 4bbls or even 2, hence the different ratings for 2 and 4bbls. Go for it.
 
well i guess what i really want to ask is would two 850s still function well on my combo which is 505" RB 10.5-1 compression, cnc ported edelbrock heads flowing 330 cfm at .600 lift, solid flat tappet cam 254/260 duration at .600/.615" lift, 4000 stall converter, full manual valve body, 3.91 gears and 28" tall tire

the plan is to sort the build out with a victor intake and a single 850 dp i already have and then when the time comes switch to the tunnel ram.

if two 850s would work well id just purchase a second one but if theres some reason it'd be too much airflow id happily buy two used 750s and rebuild them

like i said i just never see anyone running dual 850s and was wondering if there was some reason they would not work or tended to be troublesome
 
You could always pick up a used 850 and toss it on along with yours and try it out. If you don't like it, you could always sell them and pick up a couple 750s.
 
mopowers said:
You could always pick up a used 850 and toss it on along with yours and try it out. If you don't like it, you could always sell them and pick up a couple 750s.
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thats what im thinking ill do, i just find it odd everyone goes with 750s or dominators and no one ever goes in between
 
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