OK, i have everything together for the super six conversion. Doug sent my duals and I'm ready to go. Does anyone know the aprx horsepower increase i can expect by making the switch? I have a NOS 2BBl Holly and electronic igntion kit. I will also be adding dual exhaust pipes. I do not have a new cam nor have I done any milling of the head yet. thanks

Keni

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isaiah6:8
www.kenithomas.com

NOS 2bbls holley 2280?, 2300/350 cfm?

10-15 hp with "stock ish items and dual exhaust"...you may see a bit more if you massage the head, plane for compression, dial in the timing, use the 350 cfm Holley....

-D.Idiot

Those horsepower figures are deceiving. You won't feel much more torque, but you will be able to spin your engine up to around 5K with a freedom that is just not there with a one barrel. The one barrel starts to run out of steam pretty seriously by the time it hits 4K, and the 2 barrel will pull higher. That means when the transmission shifts take place, either auto, or manual, it drops down into a better rpm range for the slant. I felt l feel like I got 30 more HP with a two barrel.
Sam

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I'll go along with that, although I don't think my engine (all stock) will pull much over 4000 RPM. I think it also relates to how sad a state of tune the 1-barrel is. In my case, it was very sad.

I used a 318 BBD, and it runs perfect BTW.

All that is coming off soon...

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It's a Slant thing. Even I don't understand.

1974 Duster, EFI /6 soon to be turbo...

Get that Monkay! Get that nasty thing!!

I take it that's where the EFI goes back on!


-D.Idiot

its a NOS 318 2BBL. thanks for the figures. I'll take pictures of the conversion as I go and post them up. Doubtless, I'll be asking for help with the process.

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isaiah6:8
www.kenithomas.com

I did the conversion using the MP M1 manifold and the stock exhaust manifold with a 2 1/2 inch pipe from the flange on back. Not much difference in takeoff, but on the highway there is an enormous difference. From about 50 mph it feels like a rocket compared with before. And Im still running breaker points.

Ive having some problems Im still trying to sort out, but the highway performance is a huge improvement.

I think you might be right about the PRM not being really there until I put the Dutra Duals on, and then the electric fan. Getting rid of the fixed fan blade freed up some high RPMs. But, I think the 2 bbl is needed to get there even with the other s mods. The bit about improving the highway driving is right on also, especialy if you want to kick down into passing gear. With a 1 bbl you barely have enough umph to get it to shift back up into third, while with the two barrel you move right up to the 2-3 shift. On my car, all the things I've mentiioned happened before I installed the new motor, and changed over to the manual transmission.

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maybe my engine is really worn out but it has no bottom end it still feels a 1bbl. I have a factory iron intake and a step exhaust 2 1/4 to 2 1/2 and it wont spin the tires! now the other carb I took off for this one was a beast but it wouldn't idle to save its life. all were bbd's

Start investigating the basic condition of the engine to figure out what is wrong. Do a compression test first. All cylinders should be within 10 lbs of each other, and should be about 140 lbs or so. If it runs well with one carb in the high speed circuit, and runs well on the other at idle, maybe you should rebuild the better of the two cabs. Test the throttle shaft and see which one is the tightest. Those are good carbs when tuned right. Check your PVC valve and see if it is clogged.

Check your electrical system and see if it is breaking down becaue of high resistance in the primary wires. Do a basic tune up if needed. PUll the plugs and check them. Replace the plug wires. When were they changed last? If you have the stock distributor, it is a points set up. Those can work fine when tuned, but they do wear out, and need to have the points replaced. When I bought this '69 Dart, the points were welded to each other, and the arm had rusted through. It was still runnning because the contact was being made and broken when the two rusted through parts came together and then seperated!

Check for vacuum leaks. PUt a vacuum pump on each hose and see if the device it goes to will hold a vacuum. Some devices are supposed to leak down at a specific rate. You will need a manual to tell you how long they are supposed to hold a vacuum. It sounds like maybe there is an internal vacuum leak, or blockage in the carb that does not idle. Check the base gasket, and see if it has delaminated and is being sucked up into the carb from below. Check your fuel filter. Maybe it is clogged.

I have more or less put these things in order of importance, but any one of them will cause an engine to run poorly. The comprssion test will tell you if your engine is worn out. Good luck.
Sam

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Oh Yeah, I forgot valve adjustment.

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What is your final drive gear? Tire size with rear gear. My Duster is a different beast with smaller tires on back. My rear gear is a 276:1, the tall tires I got now kill the off line power.

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ifyoubegintothinkyou'relosingcontrol...it'salreadygone

I just replaced my BBD with an NOS I bought at Carlisle this year.
I took off a BBD that I rebuilt. What a difference. Lousy leaks at the shafts.
My carb is for a 78 Dodge 318 Truck according to the numbers on the tag.

I have clocked the new MPG to 20MPG with a kick in the pants.
I have not really setup the carb yet either. I will have to break off
the plastic stops to tweak it.

But for now it runs much much better.
Good luck in doing your conversion. You will NOT be sorry you did it.

Matt

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67 Dart GT convertible
"225 Slant 6"
Super 6 and 2.25" exhaust.