To TQ or not to TQ?
#2822910
09/20/20 01:27 PM
09/20/20 01:27 PM
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Joined: Jan 2003
Posts: 28,071 Irving, TX
feets
OP
Senior Management
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OP
Senior Management
Joined: Jan 2003
Posts: 28,071
Irving, TX
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I'm finally getting back on the 440 for the Imperial. It's been down WAY too long and I want to get it running. This thing is being built as a cruiser and road trip machine. I live in fairly flat low altitude DFW but there's no telling where I'll end up with this thing.
The car: 1972 Imperial crew cab. 5300 lbs wet. 3.23 TrueTrac and 255/70-15 tire (29" tall) and 727 transmission. I have a 518 lock up trans and Ultra Bell waiting to go in some day.
I've worked really hard to come up with an engine build that will give me a big flat torque plateau in the cruising rpm range. As much as it feels dirty to say, I am willing to sacrifice top end power for big fat torque.I want as much efficiency as I can get out of this beast, too.
Here's the build so far: std bore 440 Icon flat top pistons stopping .009" below deck Cometic .027" gasket. .036" quench with 10.2:1 compression. Edelbrock heads Ceramic coated Hedman shorty headers (1-3/4" primaries, 2-1/2" collector) Comp cam 261 advertised, 218/218 @ .050, .463/.463 lift, 110 separation. Planned exhaust will be 2-1/2" dual exhaust with X pipe and large relatively quiet mufflers.
Playing with the old Desktop Dyno software said I'd be bumping over 500 lb/ft from 2800 to 3700 and top out around 420 hp.
When the engine gets buttoned up I'd like to take it to the local engine dyno for cam break in and see what it really does.
I originally picked up an old Edelbrock CH4B intake due to the low hood clearance and I planned on dropping on one of the Street Demon carbs.
Nostalgia is tugging at my heart strings and I really long for that old Thermoquad howl at WOT.
I could flip the CH4B and pick up a Performer (NOT RPM) intake and nab a reman TQ from Summit. It would give me the sound I want and the crisp throttle response of those small primaries. If I did this, I'd slap the intake on the mill and take out part of the plenum divider.
What do you guys think? Stick with the CH4B and Street Demon or give in and go TQ?
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: To TQ or not to TQ?
[Re: 340SIX]
#2822969
09/20/20 04:31 PM
09/20/20 04:31 PM
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Joined: Jan 2003
Posts: 28,071 Irving, TX
feets
OP
Senior Management
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OP
Senior Management
Joined: Jan 2003
Posts: 28,071
Irving, TX
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Retro_fit Fuel Injection kit and never look back. I did have a TQ on my 1972 340 in 1980 till 1982 it was,great till it stopped being great in 1982. It was never right again. So put tge Holley Spread Bore replacement instead it was 100% and was,easy. Until I went with a full in crazy motor I've seriously considered EFI on this thing. I'd do it in a heartbeat if I could get that legendary sound. I'm tempted to run my old TT440 EFI manifold but I don't think it will fit in the car.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: To TQ or not to TQ?
[Re: feets]
#2823007
09/20/20 07:02 PM
09/20/20 07:02 PM
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Joined: Nov 2004
Posts: 25,050 Texas
GoodysGotaCuda
5.7L Hemi, 6spd
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5.7L Hemi, 6spd
Joined: Nov 2004
Posts: 25,050
Texas
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Retro_fit Fuel Injection kit and never look back. I did have a TQ on my 1972 340 in 1980 till 1982 it was,great till it stopped being great in 1982. It was never right again. So put tge Holley Spread Bore replacement instead it was 100% and was,easy. Until I went with a full in crazy motor I've seriously considered EFI on this thing. I'd do it in a heartbeat if I could get that legendary sound. I'm tempted to run my old TT440 EFI manifold but I don't think it will fit in the car. Holley does make a spreadbore Sniper setup, I suspect it would sound similar? Nevertheless, I've done a Sniper and a FiTech, no more carbs for me. Ever!
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Re: To TQ or not to TQ?
[Re: GoodysGotaCuda]
#2823040
09/20/20 08:11 PM
09/20/20 08:11 PM
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Joined: Jan 2003
Posts: 28,071 Irving, TX
feets
OP
Senior Management
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OP
Senior Management
Joined: Jan 2003
Posts: 28,071
Irving, TX
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Retro_fit Fuel Injection kit and never look back. I did have a TQ on my 1972 340 in 1980 till 1982 it was,great till it stopped being great in 1982. It was never right again. So put tge Holley Spread Bore replacement instead it was 100% and was,easy. Until I went with a full in crazy motor I've seriously considered EFI on this thing. I'd do it in a heartbeat if I could get that legendary sound. I'm tempted to run my old TT440 EFI manifold but I don't think it will fit in the car. Holley does make a spreadbore Sniper setup, I suspect it would sound similar? Nevertheless, I've done a Sniper and a FiTech, no more carbs for me. Ever! You may be on to something there.... Features:
Available in 3 Finishes - Classic Gold, Shiny and Black Ceramic Designed to deliver the signature Rochester Roar at Wide Open Throttle!
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: To TQ or not to TQ?
[Re: feets]
#2823205
09/21/20 10:32 AM
09/21/20 10:32 AM
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Joined: Apr 2007
Posts: 2,924 Calgary, Alberta Canada
a12rag
master
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master
Joined: Apr 2007
Posts: 2,924
Calgary, Alberta Canada
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I have always had great experience with TQ's . . . . I would rebuild to FACTORY specs, following the steps they have for them . . . ran great, good mileage, great throttle response. But, in today's world . . .yeah, I would seriously consider an FI setup. I am thinking for next year, I might go to FI on the Sport Satellite. I should have probably done that when I first put it together . . . but that was almost 10 years ago now. The Edelbrook AVS has worked pretty good, but think I could get 4-5mpg more using FI . . . anyhow, yes, know it is more $$$, but if you have to buy a TQ and then rebuild it, and need parts, you are probably getting close to the FI cost . . .
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Re: To TQ or not to TQ?
[Re: a12rag]
#2823303
09/21/20 02:05 PM
09/21/20 02:05 PM
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Joined: Jan 2003
Posts: 12,286 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
Joined: Jan 2003
Posts: 12,286
Benton, IL.
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but think I could get 4-5mpg more using FI . . . anyhow, yes, know it is more $$$, but if you have to buy a TQ and then rebuild it, and need parts, you are probably getting close to the FI cost . . . I do not agree with either part of your statement. A properly tuned carb and ignition would be very close in mileage to a retrofit throttle body kit on a wet manifold. Maybe exactly the same. Port injection and a dry manifold might do better, but that is not what we're talking about here. As to the cost, how about a real world break down of the costs of each that led you to that conclusion? And are you allowing anything for all the extra labor that an FI install would need?
Master, again and still
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Re: To TQ or not to TQ?
[Re: DaveRS23]
#2823323
09/21/20 02:47 PM
09/21/20 02:47 PM
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Joined: Jan 2003
Posts: 28,071 Irving, TX
feets
OP
Senior Management
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OP
Senior Management
Joined: Jan 2003
Posts: 28,071
Irving, TX
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but think I could get 4-5mpg more using FI . . . anyhow, yes, know it is more $$$, but if you have to buy a TQ and then rebuild it, and need parts, you are probably getting close to the FI cost . . . I do not agree with either part of your statement. A properly tuned carb and ignition would be very close in mileage to a retrofit throttle body kit on a wet manifold. Maybe exactly the same. Port injection and a dry manifold might do better, but that is not what we're talking about here. As to the cost, how about a real world break down of the costs of each that led you to that conclusion? And are you allowing anything for all the extra labor that an FI install would need? As an EFI veteran I will say EFI will cost more. Properly tuned, the two will have comparable numbers. The differences will be in cold start and the EFI always refining its tune for the conditions.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
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Re: To TQ or not to TQ?
[Re: feets]
#2823332
09/21/20 03:06 PM
09/21/20 03:06 PM
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Joined: Jan 2003
Posts: 28,621 Shopping @ HoBo Fright
340SIX
Doc Flappergas's Evil Twin
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Doc Flappergas's Evil Twin
Joined: Jan 2003
Posts: 28,621
Shopping @ HoBo Fright
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I am good at spending others money. They also had me at Designed to deliver the signature Rochester Roar at Wide Open Throttle!Retro_fit Fuel Injection kit and never look back. I did have a TQ on my 1972 340 in 1980 till 1982 it was,great till it stopped being great in 1982. It was never right again. So put tge Holley Spread Bore replacement instead it was 100% and was,easy. Until I went with a full in crazy motor I've seriously considered EFI on this thing. I'd do it in a heartbeat if I could get that legendary sound. I'm tempted to run my old TT440 EFI manifold but I don't think it will fit in the car. Holley does make a spreadbore Sniper setup, I suspect it would sound similar? Nevertheless, I've done a Sniper and a FiTech, no more carbs for me. Ever! You may be on to something there.... Features:
Available in 3 Finishes - Classic Gold, Shiny and Black Ceramic Designed to deliver the signature Rochester Roar at Wide Open Throttle!
Last edited by 340SIX; 09/21/20 03:08 PM.
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Re: To TQ or not to TQ?
[Re: feets]
#2823409
09/21/20 07:39 PM
09/21/20 07:39 PM
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Joined: May 2019
Posts: 6,324 nowhere
Sniper
master
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master
Joined: May 2019
Posts: 6,324
nowhere
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As an EFI veteran I will say EFI will cost more.
Properly tuned, the two will have comparable numbers. The differences will be in cold start and the EFI always refining its tune for the conditions.
As someone who is fuel injecting the flathead in his 51 Plymouth, the microsquirt controller alone costs more than two new 1bbl carbs, much less all the other stuff EFI needs. I have a spread sheet going detailing most of the expenditures. But my setup can also control the ignition, something a carb can't, it will also be able to compensate for alcohol in the gas, something a carb can't. So there are some additional benefits to EFI that a carb cannot match.
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Re: To TQ or not to TQ?
[Re: SRT6776]
#2823423
09/21/20 08:00 PM
09/21/20 08:00 PM
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Joined: Sep 2005
Posts: 12,481 Chino Valley
RodStRace
I Live Here
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I Live Here
Joined: Sep 2005
Posts: 12,481
Chino Valley
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1st, great to hear the IMP is back on the front of the stove. Always admired that car.
2nd, I an curious why you aren't going with a stroker. The numbers you listed are healthy, but if I were to build a fresh engine with a decent budget, it would have a few more cubes and a taller gear to keep the RPMs down. 40-50 year old rotating assembly parts?
3rd, I love the TQ sound too and the 'coasting on primaries' deal. I'd really look into a dry intake with low height and long tubes to tune for the same RPM as the rest of the build (under 4500) you have talked about machine shop and fabrication equipment before. I'd imagine that you could come up with a small/huge throttle body and the intake to head plates. The tubing would be the part that would require a bunch more effort, but would result in something special. Also, having 2 TPS inputs to map properly would take a bit of time. If you use the TQ, my main concern is all the stuff that is in gas these days. Will the body hold up to warm temps (I assume you aren't going to run a 160 tstat) and the various oxygenates and other junk in current gas?
4th, Is this going to be NA? I appreciate the E heads being new and lighter. Will they be a bit much for a stock size, low RPM engine? The cam seems fairly mild, which means fairly high static compression plus mild duration, so the quench better be dialed in for optimum timing without pre-ignition.
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Re: To TQ or not to TQ?
[Re: JDMopar]
#2823534
09/22/20 08:40 AM
09/22/20 08:40 AM
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Joined: Jul 2003
Posts: 4,793 Holland MI Ottawa
2boltmain
master
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master
Joined: Jul 2003
Posts: 4,793
Holland MI Ottawa
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Street Demon is a modern take on a carburetor implementing the best attributes of the Thermoquad, Quadrajet and AFB. Designed by a guy who was an engineer at Carter in the 60s and 70s. If you go carburetor go all new and get the phenolic body of the SD.
Keep old mopars alive.
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Re: To TQ or not to TQ?
[Re: RodStRace]
#2823544
09/22/20 09:32 AM
09/22/20 09:32 AM
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RWG75
Unregistered
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RWG75
Unregistered
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If you use the TQ, my main concern is all the stuff that is in gas these days. Will the body hold up to warm temps (I assume you aren't going to run a 160 tstat) and the various oxygenates and other junk in current gas? I'm running TQs on 5 different motors right now and some of them have been installed for a least a decade. They seem to stand up to modern gas just fine.
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Re: To TQ or not to TQ?
[Re: ]
#2823764
09/22/20 06:47 PM
09/22/20 06:47 PM
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Joined: Sep 2005
Posts: 12,481 Chino Valley
RodStRace
I Live Here
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I Live Here
Joined: Sep 2005
Posts: 12,481
Chino Valley
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If you use the TQ, my main concern is all the stuff that is in gas these days. Will the body hold up to warm temps (I assume you aren't going to run a 160 tstat) and the various oxygenates and other junk in current gas? I'm running TQs on 5 different motors right now and some of them have been installed for a least a decade. They seem to stand up to modern gas just fine. Good to hear! I don't know enough about plastics to be able to discern which are immune to which chemicals.
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