Just recently installed a new (stock)coil, plugs, wires, edelbrock intake, and 600cfm edelbrock carb on the fury's 318. Had the tranny rebuilt with shift kit installed. We took it out for a test run last night and it seemed to cut out on WOT. I set the timing at around 10-12*. I know it is past 10* because the stock timing tab will only show 10*. Lol. I set timing at 1000rpms. <<<<<<Could this be my problem from the start. I also removed the vacum advance and plugged the line to the carb to set initial timing. It seemed as later through the night we advanced the timing little by little and it seemed to get better. I dont want to go to far. B/c I am afraid something bad might happen. I dont know what main jets or metering rods are in the carb. It is brand new and dont have the manual in front of me to tell you. What else could be the issue and what advice can you guys give me to look at.

Thanks.

Chris

 

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Sir, you and I are are in the same boat!
Since I got on this forum in April I have been asking question after question trying to resolve this problem with my 340.

Okay in short, I have not solved it yet.
What Have I tried on top of the usual plugs, wires, new distributor, distributor cap and rotor, timing adjustments,fuel types, pressure regulator adjustments, carb rebuild etc...............

My carb was a Carter 600 cfm AFB (which is the equivalent of the Edelbrock 1405 carb). I read the Edelbrock ad and ordered what they sell the carb with:
Metering Jets Primary .100, Secondary .095; Metering Rods .070 x .047; Step-Up Spring orange.

For the step up springs you have to order the kit that gives you a range of choices. I ended up replacing the Orange springs with Red and it did do a lot better, anything I did to that carb to increase the gas flow made it better. Including running the A/F mixed a little rich. But it never completely solved the problem.

I finally replaced the Carter with a Holley 650 double pumper with manual secondaries. Problem solved right? NOPE!! I put two 1" 4 whole carb spacers under the Holley and the engine runs the best it ever has. But the flat spot is still there and chokes if I punch it down from a dead stop (like it always has).

I should also tell you I have a Edelbrock Torker 340 intake manifold. This is a 'single' plane manifold and research tells me they are meant for higher rpm performance. Single plane for high rpm's and dual plane manifolds for lower rpm's. Which my experience tells me is correct as the engine runs like a raped ape once she is running down the road.

Dual plane manifolds are supposed to give you better throttle response off idle because they have a smaller and longer plenum. This gives the air more velocity, from what I have read anyway.

My current train of thought:
Replace the single plane manifold with a dual plane and/or get a smaller carb. I am thinking that the 600 and the 650 cfm carbs are to large in that the supply to much air. More gas seems to help but I think it's to thin of a line between lean and rich with the single plane manifold and that large of carb. Plus any carb sizing I have read recommends around 500 cfm for my 340.

Here is a list of links I've saved while trying to find the answer, please let me know if you solve it.

Tuning Tips
Edelbrock Tuning Tips
Carter Carb Sizing
Using a Vacuum Gauge
Edelbrock Manual
Car Specs
Carb Spacers

Joe.

 

Thank you so much for the reply... Really appreciate it..

I spoke to one of our service men. And it seems my brother slammed it together quickly. It seems it also backfires through the intake when you stab the throttle. Seems the timing is not set on the compression stroke and it might be to far advanced. Going to re-do the timing procedure. Set timing at 0* on tdc on the compression stroke. Set the idle to where the "timed port" just barely has no vacume. Set the idle adjustments. Then adjust timing accordingly.

The intake we have is a dual plane intake. Its the Edelbrock Performer intake for a 340. Matched up pretty good. Just have to get the kickdown linkage figured out along with the throttle cable end linkage to the carb. We dont have the stock throttle cable end linkage. Where the tranny kickdown and the throttle cable mount to.

Where can I get these at????

Wish me luck.

 

I saw throttle linkage mounts at Auto Zone the other day, might be what you are looking for it's hard to say.

Backfiring through the carb is what I get when I have the A/F mixture to lean, rough idle when it's to rich. I've read that long term damage can be done when running to lean, better rich if not sure.

When I bought my truck I ran out and got a cheap timing light, it works okay but I did not realize you can get an adjustable timing light that allows you to dial in timing way beyond the marks on your balancer 'without' the use of timing tape. In other words you can set your timing at 34 deg BTDC @ 2500 rpm just by dialing in the light. I would really like to get one.

Please keep posting your progress, and Good Luck
Joe.

 

Get one at Mancini Racing .com

 

Try going up to a 50 cc accel pump on the primary...also go up on your shooter size...if your cam is big then your running lean when you punch it...same deal with my 440...rolling start no problem...WOT at a stop it stumbles and backfires...I went up on my shooter size and it helped..I going up to a 50 cc pump and then shooter...I spoke to a Holley tech for 15 minutes on this subject