Dual fours options and alternatives?

[Michael C Henry]

I had a thread before that got dumped in the server feascoe. I have Dove alluminum tunnel wedge intake with inline dual fours on a 427 FE . It came with two 1860 Holley carbs with vacum secondaries. The cam went flat and that and other repairs took me the better part of two years to get back to this point.I'm looking for advise and guidence.The carbs came with the usual metering plates inside the secondary float bowls. It was set up to run the Virginia City hill climb, at about 5,000 ft.When I brought it to western Washington at near sea level,The Emmission testing said I had a lean missfire.I installed two kits from Quick Fuel Techonogy that has a anodized plate that accepts replaceable jets and a notched float. I went with #68 jets .Then the cam went flat .I pulled the engine and the ordeal was on. When I first restarted the carbs just druelled fuel.One thing I tried a pair of 8.5g power valves (mistake )valves open too long. cleaning the air bleeds slowed a lot of that fuel but the plugs still fouled in a twenty minute drive.So now I have 3.5 g PVs to get a good vacum baseline.
Now the current question The carbs came with light blue accelerater pump cams and 30 cc pumps.the cams were at full stroke at the first third or less of throttle travel. Ive been messing around with the 50 cc pumps and the accelerater cam that came with them # 664.It has a gradual ramp that is even untill full throttle. The diaphram in the 50 cc pump appears to be smaller( to make room for the pleats) than the 30cc diaphram . The fuel shot appears to be about the same other than it keeps squirting through the full throw of the throttle. I have two of the cam kits.I have the old housings.levers, and new diaphrams for 30 cc pumps .
I had asked about the Road Demon JRs as dual fours.They are only reccamended for cams upto 220° My new cam is a Comp Cams solid lifter cam 242° intake and 252° exhaust.Ive e-mailed Barry grant with no response . Any input or disscusion ?

[Michael C Henry]

More back ground. The first time out I had the timing off Turned out It was 12° after tdc.Fuel drueled in. I cleaned the air bleeds and stopped a lot of the fuel . went on a ride belching and backfiring got so bad I had to be towed.Reset the timing 12°bftdc works great.Thought I had it under control . A twenty minute run to Lakewood and I could tell the plugs were fouling.I took everything appart and cleaned it all. I found one bad gasket on one carb the gasket between the mainbody and baseplatewas wrong butterfly holes were crrect size butthe outer edges went inward exposing a slot on either side that went from primaries to secondaries at the middle of each side. I had to buy a Holley Trick Kit to get the correct gasket ( one of four base plate to mainbody gaskets in the kit I got so focused on that gasket that I forgot the primary metering block to mainbody gasket.The gas came right out..3.5 g pv's at least untill I can get a good vacum baseline.I installed a 1/2" 10x32 ss allen socket set screw for the secondary idle setting.I can get to it with the carb installed to adjust the secondaries.I opened the secondaries untill the slot was exposed as much as it was wide,making a square. I had to use a drop of super glue in the hole let it dry to get some drag on the screw.
I bottom tapped the six holes in each carb that held the metering plate to mainbody and re-placed the original( odd sized) clutch head screws with 8x32 ss allen socket countersunk screws .550" long.
I have an optional hole in the dual four linkage so both carbs end up at wide open at the same point .
If I think of something Ive else I've done I'll bring it up

[Excaliber]

I dumped my twin 660 Holleys with 50 cc center squirters and mechanical secondarys. There were just a pain in the butt for fouling plugs etc.

I went with twin 600 Holley vac secondary and 30cc pumps. That was WAY better and the 30 cc pump shot was fine. Not sure why you would need 50 cc unless your vac secondaries are kicking in to fast. I'd try a heavier spring to slow down the secondaries and go with 30 cc

427 FE dual fours which recently "wiped a cam lobe". Engine out for a major redue. Which I HOPE won't take two years!!!!

[Michael C Henry]

The 50 cc thing was a whim.but I have to say I get accellerater squirt through the full throttle range.
I rewired, changed the fuel system front to back, seats, dash redone and covered, glove box, gauges , master switch,wipers parking automaticly, heater and defroster w/ ducts, steering ,ignition box, cooling system ,etc. I want to get it right so I can turn it over to a professional to have top, side curtains, and interior done. Want next summer to be grand.
Oh ya! I have two of the vacum secondary spring kitsnot opened a pair of quick change tops are installed and a new pair of adjustable secondary diaphram housing with an adjustable needle valve stiil in box not installed yet.

[Excaliber]

Hmmmm,,,,,, I think I see why it took two years, I also think I'm in trouble.

You see I plan to re-do the fuel system, wiring, paint the frame, change out some gauges, up-grade the cooling system etc. Does all that stuff and re-build the motor take two years?

..yeah, I'm in trouble

[Ron61]

Ernie,

Just 2 years !!!

Ron

[Michael C Henry]

I converted the tank from pipe bungs to A&N bungs two pickups and a drain and added a return in the right front corner. The pickups are in a forward facing sump. Each pick up sucks fuel from a different level of the tank by means of a different length pieces of 5/8" ss fuel line flared at the fuel entry end. Each side leaves the tank goes into a 60 micron filter-check valve - 100GPH 17 PSI Carter electric pump then "Y" together, all #8 A&N Leaves the "Y" in 5/8" fuel line to the firewall to a Berry Grant 5000 fuel filter then to a Berry Grant diaphram adjustable fuel log set for 4.5 PSI . The Fuel log hangs from two short and different length SS lines off of each carb, fuel not needed to achive fuel pressure is returned to tank .Fuel pressure is 4.5 on one pump and 6 with two pumps running.As I said fuel is picked up at different levels of the sump normaly operate off the higher system,when the system stumbles turn to the second lower system and start looking for a gas station. Both pumps were for competion . I had to cut holes in the rear tube coming off the main frame tubes for pass throughs for the fuel lines (two supply and one return).Had to cut the hole and fit it to a peice of smaller rectangular steel tubing and weld them at both ends making a pass through on each side . Pass throughs are about 2/1/2" by 1 1/8" inside. Area in pass through not filled with tubing has closed cell foam cut to fit stuffed in to it
Almost every project I took on took around five weeks to finish between ordering ,waiting ,modifing ,reengineering etc. .The engine was a lot longer.I found out that cash made the difference. The machinist had been burnt by local soldiers that dropped off projecrs and never came back.Most of that first summer was lost and that is how I got started on all the different projects.Little things like the wipers not parking , indicater lights for fans and fuel pumps.a master switch that the driver could reach while belted in, etc.Every project came with unknown revalations.Thing are allways more involved than they appear.Up to now everything I've done is a success.It wasn't easy or cheap or fast.The people responding to the club forums helped the most.

[Michael C Henry]

Thought I had it. It sounded so good.I didn't see any gas drueling in.It was running good enough that my wife came along for the ride. got about three miles from home ten minutes tops and it started runnung ruff.A block later and I turned it around .It was getting worse,Idle seemed ok but off idle was terrible..I'got it home you could see the fume cloud in front carb ,plates look wet.I'll bet the plugs are fouled again.I checked the float levels again, as right as could be.
When I removed the original pv's they had two gaskets .What was that about?

[Michael C Henry]

I have a pv diaphram tester.The 3.5 g valve I had in it didn't leakvacum. The 6.5g pv I received with the trick kit doesn't leak vacum .The two old 7.5g pv's that came to me in the carbs leak vacum ,slight but they leak vacum. I didn't have this problem before I removed the old pv's . I'm wondering what to check next.
How do you check a power valve to see if isn't sealing off the gas ?

[G.R.]

I hate Holley's for the very reasons you are going through.If it is not jets it's power valves or Trick kits, or rebuild kits, just to get a spring or gasket not sold seperately By the time you spend the $$/time to get one into tune you could have probably bought a new carb--and you are dealing with 2 of them. Good luck. I gave up on mine.

[Rick Parker]

Michael you have a P/M

Rick

[Michael C Henry]

I thought I saved the Braswell link it's not here. They do not mess with 1850 but they looked like they had a couple of books.Search doesn't get it either. Help.

[SCOBRAC]

IMHO,

Both the 1850 and the 4220 (600 and 660 cfm holley carbs) are viable alternatives. As are the dual 390 or 450 cfm units. Your 427, 428, 454 et al will never pull more than 900 cfm. That said I really think for day to day simplicity the 1850 vacuum secondary is the easiest to live with. For full disclosure I run the 660 cfm carbs for max power and 450's for cruising.

I really love my 660 cfm Holley mechanical secondary carbs but they are a compromise, all carbs are. What works well at 2500-3500 rpm is often different than what will work at 8000 rpm.

If you are fouling plugs I suggest pulling a vacuum test. Your power valves shouls be at least 3" of vacuum less than your vacuum at idle, That is if your engine idles at 12 your power valves should be a 8.5 (standard valve for a holley), but if you get 5.5" of vacuum at idle you might want to use a 2.5 or 3 power valve.

A good Holley carb book will help a lot, good luck!

[misfit41]

Sobrac,,
you seem to have experience with dual quads,,can you give me your opinion ?
My Builder {KeithCraft} is waiting on me to send carbs for my new engine.An alloy 496 shelby,Stage 3 eldebrock heads,tunnel wedge intake,should make in excess of 700 hp,cam lift is 740 ,,duration 244/247 if memory serves,dont quote me there.Ok Heres the question,I have a pair of original 780 cfm c5af Bu and bt,3410 and 3411 respectfully,the carbs are original and would need fresening or blueprinting.There still on an original no number med rise intake ,I hate to alter them much,and I wonder if there is a better choice for this motor ,obviously it should suck lots of air,not sure about 1580 however.I also sort of hate to put any thing used since I am in this deep,,whats your opinion ?
thanks,Tim

[Michael C Henry]

I got tired of messing around with the 1850's the way they were. I sent them to Quick Fuel Technology.they made them look as new .I had to realy examine them to see if they were infact the carbs I sent.
In their effort to make them look period correct they removed Things I was using .Like the vacuum nipple from booth the base plates below the primary float bowls.They were the only vacuum source ports I had. They removed the choke cam from the primary shafts.I had removed the mechanical chokes for shipping and they figured I didn't use them .I use the fast idle feature during warm up .They kept my secondary quick spring change covers. They removed the center three screws that held the base to main body .I found they do that on open intakes to keep the screws from falling into the engine .I can now see that. They removed all the epoxy that I had paid George Anderson to install in the unused channels in the underside of the baseplates. I now have to redo. I'm waiting for my missing parts to arrive from QFT now. I bought a new package of Moroso # 35560 epoxy.
What ever carbs you chose look underneith the baseplate and compare everything that would be outside the mounting flange of your intake manifold.Potential vacuum leaks. I mount carb with one gasket to manifold because of hood clearence issues and I don't need to add another 1/8" thick plate and gasket.

[misfit41]

Thanks for the info Mike,
Its funny you brought up quick Fuel,I have their catalog beside e now,I live less than an hour from them,Let me just say that here they dont enjoy a very good reputaion,but I am speaking only from "he said /she said " I hope your deal works out ok,,
regards,,Tim

[Michael C Henry]

They sent the parts as they said.I've refilled the unused vacuum channels of the underside of the baseplate.Reinstalled the vacuum nipples, fast idle levers, and quick change spring covers. Stiil didn't get a list of parts that were installed or operations they did.I have just noticed that they removed the white plastic whistles from the float bowls and replaced them with a small brass devise in the vent window.I'm not familiar with these what are they supposed to do and are they better than the whistles?

[Michael C Henry]

I have all that stuff installed .Now I find where there was once plastic fuel bowl baffels "whistles" There is now a small brass deflecter that tries to cover the rectangular vent hole diagonaly. I was advised that the whistles are not for the side hung floats and may stop the float from closing the needle and seat. And would only be needed if the vehicles movements were aggesssive like starting , stopping, turning sharply, etc. What is a Cobra replica about? I bought a pair of new extra floats that I entend on experimenting with .I plan on notching the float to clear the whistle.Another reason for a single four.