Need Intake Guidance ...

[DataMax]

I recently purchased a '66 Coronet with a 440 RB engine. The engine is set up as follows: 440 bored .030 over, 10.5:1 forged pistons, steel crank with 6-pack rods (rotating assembly was balanced), Mopar 280/280 x .474/.474 cam w/titanium valves and HD springs in 452 heads. On top is a Weiand 7512 w/an 850 double pumper. It's all fired by a MSD ignition. Spent gas is removed by way of 1 3/4 Hedman headers through a 2 1/2" exhaust. The engine is backed by a 727 with a shift kit and 1700 stall TQ. Power is moved to the ground via a .323 sure grip.

Around town this thing is a MAJOR Mutt that wants to do nothing more than foul plugs. In my mind it is over carberated to beat heck!

In my garage, siting on the self are the following parts ... rebuilt Carter 750 AVS ... rebuilt Thermoquad ('74 Vintage 850) ... Edelbrock Performer 440 intake ... and a Holley Street Dominator intake.

Now ... where do I start? What makes the most sense? I am looking for a power band between Idle and 6000. The MSD setup has a soft limiter set at 6200 and the motor with bang it all day long. Yea, the Weiand and 850 DP work great up top ... but this is to be a srteet car, a driver, with the correct third member it'll see some stop light to stop light combat.

Again I ask ... where do I start ... what makes the most sense using what I already have? Also what would be best even if it meant going out and spending some dollars?

Thank You Much!
Mark

[72Challenger]

You're right, the Weiand manifold and double-pumper carb are way to much for cruising around town. Double-pumpers really don't belong on the street, except in very limited circumstances. You'll get the best mileage and street manners with the Performer and the Thermoquad. The Performer isn't made to go above 5,500 RPM, the single plane Holley will wind higher, but not be quite as good off-idle. Still, with a 1,700 RPM stall, you would find it quite responsive when you get on it. I would say the choice in manifolds would be based on the compromise you want to make, better off-idle or better top end?

[rusty duster]

unported 452"s aren't much good past 5600 rpm,so make it work down low

[charger_dan]

1) use the street dominator manifold and thermoquad.
2) sell 850dp/weiand manifold and put $$ toward a good converter.
3) remove doors from mustangs and ricers at stoplights.

[oldguyalso]

Yeah! What Dan said! Try to remove doors on streets you don't normally drive on. They make a loud banging noise when you drive up the street again. Not to mention a lumpy street. Almost worse than pot holes.

[JLM440]

Street Dominator & 750 AVS or thermo, that 850dp is alot of carb, especially with no gear & stall..

[BlownP/M]

What about a blown power valve in that holley? That combo shouldn't foul plugs if it's tuned right. That 850 is by no means too big for what you are doing.

[rumblefish360]

Originally Posted by charger_dan

1) use the street dominator manifold and thermoquad.
2) sell 850dp/weiand manifold and put $$ toward a good converter.
3) remove doors from mustangs and ricers at stoplights.

(4) Beat chest proudly because you did the right thing!
Ha ha ha.

I agree that the 850 may be malfunctioning. I myself have a hard time in the intail set up of carbs/timing and tuning the whole package after a intake/cam swap. (IE; dual plane 600 to a single and a 750 with a cam change while I'm there.) Phaseing in the distributor and setting the timing and adjusting the carbs state of tune in idle and cruise etc....

T-Q's can be a pain to set up sometimes. They work very well when done right. A very nice street running carb with big cfm abilty when needed.

The AVS is an old time fav of mine. Use AFB rod covers so you can use current AFB rods from Edelbrock to tune that carb.

[Shaun]

Originally Posted by BlownP/M

What about a blown power valve in that holley? That combo shouldn't foul plugs if it's tuned right. That 850 is by no means too big for what you are doing.

I like the 850 DP. It's what I run on my 65 Swepty,on top of a Team G Weiand and on the street,it's fine. I have a much different combo,however. I have 10.8-1 CR,super ported 516's,240/246*- (I forget-292 adv?) at .050. ,501/.507 lift and everything balanced/blueprinted,3000 stall,TCI Comp Series Man Valve Body Tranny,3.91 Sure Grip(742),Chris Alston Ladder Bars/Coil Overs.....(I always miss something).But back to the point. My plugs load up after sitting at a light(Champion R12Y),but cleans right out. The DP would hesitate,then get it until I put a 50cc pump in the front,too(one in the back from Holley). Now it just gets it. It'll almost beat an 06 Viper when I have the slicks on. 12.10 is my latest best.
Call me and I can help you with it. You probably just need to tune it in.Or send it to me and I'll get it just right.530-263-3698
Shaun

[451Mopar]

I think it is those titanium valves. I'll trade you for some stainless steel valves

[beepbeepsrule]

Hey Campy...three words.....STAY ON TARGET!

Charger_Dan's (cool name btw!) post is dead on for now, I personalized it some...

1) use the street dominator manifold and thermoquad.
2) sell 850dp/weiand manifold and put $$ toward a good converter.
3) remove doors from mustangs and certain 383 RR's at stoplights.


Let's try that first....methinks you will like.......and the Brew-lays will wonder what-the-what! ...so let's try it first.....and I won't mind working on it again if you decide to pump it up after you try the TQ with the current engine config for a while......

[charger_dan]

Originally Posted by BlownP/M

What about a blown power valve in that holley? That combo shouldn't foul plugs if it's tuned right. That 850 is by no means too big for what you are doing.

odds are he doesn't have a blown power valve.
if he did, that thing wouldn't even be capable of running poorly.
it likely wouldn't run at all.

unless it's an old holley (built before 10-12 yrs back), a blown power valve is an impossibility. you can thank edelbrock's carb advertising for helping to perpetuate this myth even up through today.

[dave571]

I will say that generally, 850 dp isn't too big for a warmed over 440 in the right car.

BUT....

The combo is mismatched for decent street maners

The intake and carb ARE too big for 323 gears, and a 1700 rpm stall, and a heavy B body. The engine can't react fast enough to get the air moving.

The compression and cam seem to be a fairly decent match to each other(maybe a bit much compression on pump gas, but it'll work.)

With a tall tire, 391's and a 3000 stall would wake it up. Even so, I'd be tempted to use the performer intake.

Most bang for the buck, throw on the performer intake, and the avs. Even with that, I'd spend some money and get a 3K converter. 3K is fine on the street. .02

[darktone]

My brother has the same basic engine set up you do- even the same cam. He has a 6-pack set up on it and it works great. Don't have to worry about too much cfm for cruising and has plenty of cfm at WOT. Also it has the coolness factor going for it.

[DataMax]

Originally Posted by darktone

My brother has the same basic engine set up you do- even the same cam. He has a 6-pack set up on it and it works great. Don't have to worry about too much cfm for cruising and has plenty of cfm at WOT. Also it has the coolness factor going for it.

I really do like the multi-carberation look ... 3 duces, 2 fours ... buut for now I just to get it running well. Then do wheels and tires, then do a disk brake conversion, then maybe do the multi-carb thing.

For now I want to get it running good, then looking good, then stopping good.

[72Challenger]

This isn't what you asked, but I will give you some free advice anyway. You can take it for what it's worth.

I would make the stopping good part the first priority. It would be a real shame if the good running, good looking ride were to end up crunched.

[JLM440]

Originally Posted by dave571

I will say that generally, 850 dp isn't too big for a warmed over 440 in the right car.

BUT....

The combo is mismatched for decent street maners

The intake and carb ARE too big for 323 gears, and a 1700 rpm stall, and a heavy B body. The engine can't react fast enough to get the air moving.

The compression and cam seem to be a fairly decent match to each other(maybe a bit much compression on pump gas, but it'll work.)

With a tall tire, 391's and a 3000 stall would wake it up. Even so, I'd be tempted to use the performer intake.

Most bang for the buck, throw on the performer intake, and the avs. Even with that, I'd spend some money and get a 3K converter. 3K is fine on the street. .02

[dave571]

Originally Posted by darktone

My brother has the same basic engine set up you do- even the same cam. He has a 6-pack set up on it and it works great. Don't have to worry about too much cfm for cruising and has plenty of cfm at WOT. Also it has the coolness factor going for it.

CFM isn't the real issue. A 6 pack works on vacuum secondaries. It only supplies what the motor needs. The air flows in as the motor reacts. Amajor difference from the combo in question.
I agree, A 6 pack would work better here, than the 850 DP.

A double pumper just dumps it in. Works great with lots of gear, and stall. I run one on my own car. 4.10's and a converter that flashes between 3400 and 3600

Not at all a good choice with 323's and a 1700 stall.

[furz4444]

You need to have a carb with vacume secondaries or an air control valve like the Thermoquad or the Carter AVS. That double pumper is going to cause you to run very rich off idle with those two accl pumps and rich jetting. I would just try the thermoquad or AVS on your current intake. It's not that bad of an intake, I don't think I would change it out for another single plane anyway. What comes to mind for a carb for such a combo is the old 3310 780 holley. I think it's a 770 advenger now. If you like holleys. If your going to drive it alot then the Edelbrock intake and thermoquad if it will fit will give you the best fuel milage, with real good performance. I had the TQ on my 74 440 and it worked very well for me.

[turbododge]

I think I am missing the point that is being made about double pumpers. There is no reason for them to have "rich jetting" or to dump too much fuel because of having two pumps. They are much more driver dependant, as your right foot controls the secondaries instead of the airflow in the primaries, but this also can make for much more control if the carb is setup right. On a Holley DP you can have full metering on both ends, meaning you can set main jets, power valves, accellerator pump shots as well as change air bleeds and float levels. They are probably the most tuneable carb around.

Personally, if you have a car that you are going to drive hard, in anything other than a staight line, I prefer the mechanical secodaries because you have much more predictable control than any vacuum controlled secondary carb will give you. Well setup and well driven, the smoothness of the transitions with a DP can't be beat, IMHO. It is not easy to get them setup good, I will agree, but worth it.

[rumblefish360]

I think I am missing the point that is being made about double pumpers. There is no reason for them to have "rich jetting" or to dump too much fuel because of having two pumps.

Agree and disagree.
The Dp, when punched to the floor, is giving the engine more air than need be. It really isn't the engines fault, it's the rest of the combo more so.
It's the low stall and numericaly low gear ratio in a heavy car.

Those 3 things make the DP dificult to use well on the car as set up currently.
Now foot control is another story. I have great foot control until the muscle wears out from lifting the lead. LOL
Seriously, it is not as easy for others as it is for you.
A perfect example is the invention of the auto trans. I can row my boat all day. But my sister couldn't get an oar in the water if you took the boat away.
He he he he

[turbododge]

Rumble: I totally agree with what you are saying. Unless you are at high rpm, you should never take a DP straight to the floor. My point, maybe not clearly stated, was that a DP, when properly setup, and PROPERLY DRIVEN, works very well and does not go rich. This precludes anyone who drives as if the throttle were a toggle switch (on/off), as they will continually be taking the carb to a too much air, too rich bog. I think the DP gets a undeserved bad rap because folks don't know how, or take the time, to set them up properly, or they don't learn how to drive them. If you are "steering" your car through a corner with the throttle, the time lag and inconsistency of a vacuum operated secondary (as you go on and off the gas) can really give you grief ( and a spinout), but, by the same token, if you don't have the feel and patience to drive with careful throttle control the mechanical secondaries will be even worse.

For the masses, vacuum secondaries are generally fine, but for the very good driver who likes to take it to the edge, a well setup mechanical setup will perform a bit better, IMHO.

[rumblefish360]

I got the previous post and your current one is iceing on top. Good post.

I'm with T-dodge. But I myself would do different. Such is the world of cars.

[mhenesian]

Hi DataMax,

Your combo should work very well. I've run the Mopar 280/0.474" cam in the past. I'm surprised you're having trouble. The 850 DP is a little too big with that cam, but you should be able to make it work. If the Weiand 7512 is a single-plane (I can't find a listing for it anywhere !), try the Performer 440 with a 3/8" Holley thermal spacer. This will give you a good baseline.

Change the metering block gaskets in the 850 DP and check for warped surfaces and loose power valves. You can "true up" the throttle body surfaces with a high quality flat file, if necessary. Also make sure the fuel level is at or below the site plug openings. You don't want it spilling out. 76 or 78 jets front and back should work perfectly, with 6.5" power valves. If the DP still gives you trouble, bolt up that Thermoquad (remove the Holley spacer). You should have 11" of vacuum at idle with the 280/0.474" cam. If you're below this you could be having manifold sealing problems, leaks, blow by, etc...

The next step up IMO is the single plane Mopar M1. Also designed for the Thermoquad, by the way. I'm running one now with a Proform 750 DP (and I've also run all of Edelbrock's current manifolds, including the new Victor 440 !), the M1 is far and away the best single-carb manifold for the 440 in street or race trim. It's design is based on the Holley Street Dominator (Larry Shepard's own words - you can guess this from what he says in the B/RB Engine Manual).

Good luck, you'll get it all sorted out,

and an 11" torque converter will help the driveablilty a lot, but cost you lots of gas,

Mark H.

[345Dart]

and an 11" torque converter will help the driveablilty a lot, but cost you lots of gas,

Mark H.[/QUOTE]

Could you further explain this statement?
Thanks

[mhenesian]

Sorry 345 Dart,

An 11" converter (a re-built Mopar Street Hemi type from TCI or Turbo Action, for instance) is a lot looser than a stock 12" Mopar converter. Flash stall behind at moderate 383 or 440 would be 2700~3100 rpm. So in other words, just crusing along at ~40 mph, the 11" converter will have just enough coupling so your engine RPM would be ~1900 RPM. The rear gear ratio is not that important here. The converter power losses are pretty high. The 12" converter would cruise along at ~1600 RPM (this is from my memory) with tighter coupling and higher efficiency.

But step on the gas and the engine will jump to the flash stall RPM, and then pull from that point on up. The higher the rear gear, the harder the acceleration. A 10" race type converter (TurboAction, my favorite), will jump to 3900~4100 RPM when you step on it. Very raced out - Pro Street only ! Cruise at 1900 RPM, hit the gas, go to 3100 (11") or 4100 (10") RPM. Clearly not good for gas mileage, because the converter power loss is high below the flash stall RPM. High efficiency (> 90 %) above the stall RPM, but you're not going to run above the flash stall point all the time, except maybe at 70+ mph.

With the 12" converter the flash stall would be ~ 2200 RPM (my memory again). Lower torque motors (340, 360, etc...) would have lower flash stall numbers - but not much lower for 11 or 12" street type as opposed to race only converters.

See http://www.turboaction.com/conv_techtalk.html

If your motor is over carbed (ala 850 DP) and/or over cammed (>225 deg at 0.050") with too low a flash stall converter, when you hit the gas, the motor will bog bad because the flash stall point is below the RPM which is required for enough air flow to make the combo produce good torque. A "stiff" rear gearing or "tall" tires will only make matters worse.

Paul Forte at Turbo Action can explain this better than I and get you the right converter for your application. I'm very pleased with my Street Hemi converter (PN 17501) from Paul ! I also own his 10" converter (PN 17805 ST "tight"). It's very nicely built and performs flawlessly. I'm saving it for when I take my auto tranny Roadrunner off the street, for racing only.

Mark H.

[daredevil]

any body break out a jet kit to tune carbs or does everyone have an endless supply of carbs on hand and I havent heard anybody ask the a/f ratio.

[Shaun]

Of course I have a BIG Jet arsenal,to tune my 850 DP in!!! LOL!!
The thing that is missed most in this thread is the primary accelerator pump and shooter size. With his combo and the correct tuning of the carb,there should be NO bog at all and absolute streetability at ALL speeds. Shame on you guys for being so ignorant. An 850? On a 440? It's even warmed over a mite!
If it bogs,you aren't getting a good enough primary shot into the carb. On a smaller,less built engine it would be different. Any more questions?

[dave571]

Originally Posted by Shaun

. Shame on you guys for being so ignorant. An 850? On a 440? It's even warmed over a mite!
Any more questions?

It's not ignorant at all to say that a 850 dp is a bad pick on 323 geared car with a 1700 stall converter.

Tuning can make it better of course, but it's obviously still a mismatch.

[Shaun]

I disagree Dave. I tuned mine in while I had 3.23's. It is a mismatch,but there are TOO many on this and a whole lot of other sites that make an engine out to be rocket science. It is very simple.
The 850 will work without misses,or bogging and you can even get it to idle fairly lean-if that's what you're after.
The point here Dave,is that it isn't too big. It doesn't have one too many shooters either. It can be tuned in to work with that combo. A higher stall and lower gears will help-duh.