Re: 850XP Holley good for 508" RB?
[Re: racerx]
#3085783
10/13/22 03:27 PM
10/13/22 03:27 PM
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Joined: Feb 2003
Posts: 10,205 Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,205
Someplace you aren't
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A lot of 750 carbs are close for a 350 Chevy out of the box. Those guys slap those on without question. Mopar guys put small port heads on 500” engines and worry they will have poor driveability with an 850. See this a lot. This one has the 270s so bigger would be better without question.
I want my fair share
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Re: 850XP Holley good for 508" RB?
[Re: AndyF]
#3085840
10/13/22 09:26 PM
10/13/22 09:26 PM
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Joined: May 2009
Posts: 511 Temperance, MI
68 HEMI GTS
mopar
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mopar
Joined: May 2009
Posts: 511
Temperance, MI
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I ran a 1050AN on the street with my 512. I built the carb. They need a little bit of transfer slot restriction for street use but mine was absolutely a great carb. Could easily daily drive it, get decent mileage, and run high 10’s.
68 Dart GTS "HEMI" 10.30 @ 131 pump gas street car 3780# 69 Roadrunner 511 six pack 10.92 drive to track street car
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Re: 850XP Holley good for 508" RB?
[Re: 68 HEMI GTS]
#3085845
10/13/22 09:42 PM
10/13/22 09:42 PM
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Joined: Mar 2009
Posts: 2,462 Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,462
Sydney,Australia
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I ran a HP1000 (850) on my 505 with Source CNC heads , daily driver / strip . Ran great , 10.50 best dragging the brake . Great driving on the street . Went to a 1050 4500 only a small gain but more consistant - till I fitted TF270s . Then a lot faster / quicker . I ran that HP1000 on both my 440 and the 505 .
Tex
Last edited by tex013; 10/13/22 09:42 PM.
New best ET 10.259@129.65 . New best MPH 130.32 Finally fitted a solid cam, stepped it up a bit more 3690lbs through the mufflers New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm Power by Tex's Automotive
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Re: 850XP Holley good for 508" RB?
[Re: fourgearsavoy]
#3085997
10/14/22 02:02 PM
10/14/22 02:02 PM
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Joined: Dec 2021
Posts: 1,125 Loudoun County, VA
Brad_Haak
super stock
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super stock
Joined: Dec 2021
Posts: 1,125
Loudoun County, VA
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I have the QF 1050 AN on my 493 Indy head Savoy and it runs pretty strong but I'm sure it would have better street manners with that 850 XP deal. I dunno about that... one of the complaints w/ the 850/950 XPs is they may do OK on the dyno, but drivability isn't good because their tunes aren't "street friendly".
2021 Challenger 6.4L Scat Pack 1320 100% stock: 1.680, 11.894 at 113.75 (DA 175 ft) weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008] pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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Re: 850XP Holley good for 508" RB?
[Re: Brad_Haak]
#3086010
10/14/22 02:31 PM
10/14/22 02:31 PM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,496
So. Burlington, Vt.
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Had a 505 on the dyno yesterday....... pretty similar build to what the OP has outlined, The one here would be a tad milder. We used a Brawler 1050 downleg on it- https://www.holley.com/products/fuel_systems/carburetors/street_strip/parts/BR-67209After a few rounds of jet reduction, it ended up in the high-12’s/low-13’s at WOT, and 13.7’s or so at 3000rpm(50-70 hp)part throttle cruise, with 82/90 jets. That motor only used 820cfm@6300. That carb seemed to be a pretty good match for that build.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 850XP Holley good for 508" RB?
[Re: Cab_Burge]
#3086013
10/14/22 02:40 PM
10/14/22 02:40 PM
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Joined: Sep 2003
Posts: 19,388 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,388
north of coder
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What do you do about the differences in the front versus the rear throttle bore size and CFM differences feeding the cylinders at WOT? if on a single plane intake or a tunnel ram, that may take some "popcicle stick" thinking to even out the fuel distribution. on a dual plane intake [if there is such a thing for an RB], i would imagine there would have to be some fiddling as well but not as much as a single plane intake. to be clear, i have thought about this for years, but i haven't done anything about it. also, don't forget the adapters needed to bolt on the T-Quads, as i don't think there are any dual quad intakes out there that are set up for spread bore carbs. those will more than likely need work as well. i think there was a member here, ["Quick D-100" perhaps ?] that tried a pair of T-Quads on a tunnel ram, and i think he said they worked pretty well. so who knows ? just something floating around in the cobwebs of my noggin...........
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