Re: Warmed over 383 intake and carb questions
[Re: IROC78]
#3176856
09/21/23 08:49 AM
09/21/23 08:49 AM
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Joined: Jan 2003
Posts: 9,924 Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,924
Weddington, N.C.
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I don't know about the Trick flow intake but that's not a very big cam , I used to run a home ported Holley Street dominator on a 383 that made lots of torque and pulled up to 7000 on a 383.
I did the same mods to a few 440 SDs my buddy Mark 'GY3' still runs real low 11-oh's on his street driven 493.
I'm almost thinking a big single plane like the TF might be borderline "too much of a good thing" cross-sectionally for your combo. But to answer whether the ports are too small? Maybe/probably not, they probably make it that way deliberately.....because not everybody buying that intake is building a 511 Stroker low deck, there's probably a higher degree of taper (the runners are bigger at the plenum than they are to the head port.)
So not in your case, but a 383 with your combo basic combo but with only say 9.5-10:1 probably wouldn't fall out of a tree with that manifold. Your compression is the key to why your combo works as well as it does.
It's just a guess but I would think you would need at least more cam lift (to really use more of the sweet spot of those heads) before you would overtax the intake.
The carb depends more on the launch speed, if you're launching off the back squirter (assuming you have a double pumper) you could probably run at least an 850.
Last edited by Streetwize; 09/21/23 09:02 AM.
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Re: Warmed over 383 intake and carb questions
[Re: IROC78]
#3176976
09/21/23 04:15 PM
09/21/23 04:15 PM
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Joined: Mar 2008
Posts: 562 Kentucky
clovis
mopar
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mopar
Joined: Mar 2008
Posts: 562
Kentucky
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Your combo is close to my old combo and real close to my new. My old combo was .030 over 383, 9.4:1, solid flat 250@.050 .580 lift, 1.6 ratio, ported 906, 2" headers, 5800 stall. This combo was modeled after the 500HP 383 Dwayne (Fast69Plymouth) did that is detailed in the tech archives. http://www.moparts.org/Tech/Archive/bb/25.html If you have a 383 there is a lot of really good information in those two threads, definitely worth the read. Last year I tried lots of intakes and carb on my old combo. I have an RPM, TM6, Victor 383, M1 4500, Holley SD, Torker, and tunnel ram. For carburetors I have run everything from a Demon 750 all the way to a 1050 Dominator. My TM6 has had the dimples welded up and the top blended into the runners and it has proven to be the fastest on my car (3400lbs Duster). I did also use a phenolic 2" merge spacer and would say that with all the intakes a spacer most always helped, especially on the RPM. A 2" merge spacer on the RPM was a noticable difference (picked up the front wheels). My best carb has been an 4150 QF 950 Annular booster (v1.450/tb1.750), so don't be afraid to carb up, especially since you have some decent compression. The only thing I noticed with a larger carb is it requires more tuning. The 4500 2 circuit on the RPM was also a good combo using a HVC 2" adapter. On my car, I lost 2 mph when I put some exhaust on it from open headers. What I have described above is with a 3.5" exhaust (race muffler and extension to rear tires). I kept adding timing and it kept getting faster, I finally quit at 40 degrees. In the summer I will dial it back to 38 ( dist is locked out). I shifted at 6000 1-2, 6500 2-3, 6800 through the traps. If are over 3500lbs and have room for a spacer, I would likely suggest the RPM with a 2" merge spacer with an 850 or larger annular booster carb. The dual plane seems to like the annular booster and an annular booster tends to do better with a larger venturi (+1.450). You will need a fairly high stall converter and a decent gear to really make it work.
'75 Plymouth Duster Phase I 451 906/590/2-660 10.75/126 Phase II 451 Stage VI/590/1050 9.82/135 Phase III 383 906/Victor-Pump gas 11.30/119
"For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,"
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Re: Warmed over 383 intake and carb questions
[Re: B1MAXX]
#3177146
09/22/23 09:07 AM
09/22/23 09:07 AM
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Joined: Dec 2021
Posts: 1,326 Loudoun County, VA
Brad_Haak
pro stock
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pro stock
Joined: Dec 2021
Posts: 1,326
Loudoun County, VA
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I didn't look it up but a 850 is typically 1.56/1.75 So that particular 950 1.45/1.75 would be smaller. Might still be better but just pointing this out. Yep, a 1.45" venturi with an annular booster is nowhere near a legit "950"... that's just an advertising game. It's really all about venturi size / throttle bore size / booster config. From what I've seen, a 1.50" v / 1.75" t / downleg flows pretty close to a 1.56" / 1.75" / annular, although the atomization characteristics are going to be different.
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: Warmed over 383 intake and carb questions
[Re: Brad_Haak]
#3177228
09/22/23 03:18 PM
09/22/23 03:18 PM
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Joined: Jan 2003
Posts: 14,539 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,539
So. Burlington, Vt.
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Heavy street car with manual trans and not tons of rear gear, generously sized heads with big intake valves for the displacement.........
I’d run an RPM with some sort of “HP” 750 on it.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Warmed over 383 intake and carb questions
[Re: IROC78]
#3177256
09/22/23 04:26 PM
09/22/23 04:26 PM
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Joined: Jan 2003
Posts: 21,473 A collage of whims
topside
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 21,473
A collage of whims
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Like what Fast says, I think of a street combo in terms of leverage: Heavy/tall gear/tight converter vs engine output, admittedly a gross simplification, but logical to me. In a way, it distills to Velocity vs. Volume, though the curve for either needs to be considered & dealt with. Examples: big ports & cam like say a '69 Boss302 were a bit clumsy, and my Hemi 4-speed RR really liked more gear (4.10 vs 3.54). My little 292" SB 4-speed '57 Chevy from WAY back in the day flat left on everybody, every time, on the street. Big motors were a challenge near the top end. Though today we'd laugh at how small everything was on/in that motor, it had port velocity.
I thought the not-really-a-950 deal had been addressed by Holley - should be 2 different part #s, I think. The annular AVS on one of my RRs is cleaner & more responsive than its original AVS, though I suspect the original needs fettling.
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Re: Warmed over 383 intake and carb questions
[Re: IROC78]
#3177265
09/22/23 04:53 PM
09/22/23 04:53 PM
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Joined: Jan 2003
Posts: 14,539 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,539
So. Burlington, Vt.
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. So I looked up the specs on the 850 I have and it is listed at 1.56/1.69, and the 950 version is listed at 1.56/1.75 The 1.56/1.69 is a configuration I don’t care for. The “original” 850 was 1.56/1.75 The old 830 race carb was 1.56/1.69, along with the “Street HP” 850 The QFT/Brawler 850 is 1.39/1.75(chokeless) The QFT/Brawler 950 is 1.45/1.75(chokeless) The original Holley HP 950(80496) is 1.37/1.75 A Holley “Street HP” 750 is 1.37/1.69- this is the configuration I’d be using......pic your favorite brand. Obviously, you can just start with what you have and see how it works out. The main difference I’d expect between your carb and a true 750 would be in throttle response at lower operating speeds and fuel efficiency.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Warmed over 383 intake and carb questions
[Re: IROC78]
#3177274
09/22/23 05:57 PM
09/22/23 05:57 PM
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Joined: Jan 2003
Posts: 14,539 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,539
So. Burlington, Vt.
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To clarify, I don’t think a different carb/intake will make “more power” at WOT than what you already have. My suggestion was based on improving the street manners, but if you’re happy with that aspect of how it runs, then save your money.
It’s not like there’s a magic 30hp hiding in a carb swap(unless there’s something way off with the current carb).
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Warmed over 383 intake and carb questions
[Re: IROC78]
#3177293
09/22/23 06:54 PM
09/22/23 06:54 PM
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Joined: Jan 2004
Posts: 8,646 fredericksburg,va
cudaman1969
master
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master
Joined: Jan 2004
Posts: 8,646
fredericksburg,va
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.030 over 11.5 TRW pistons Torker intake 3310 Holly 509 cam, according to Wallace calc made 400 hp. Went 11.60s @ 118, in 1980 Street Hemi converter, 4.88 gears 29/10,5 tire
Last edited by cudaman1969; 09/23/23 10:07 AM.
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