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engine missing

74roadrunner440

74roadrunner440

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i have a 73 rr w a 440 509 cam dual 600 edelbrock carbs i tried to set carbs and i screwed in all the way on one carb n engine didnt stumble it seems i still have a air leak but sprayed either n carb cleaner arond intake and carbs n didnt kill engine even when i set carbs i couldnt see a noticable change in vacum w the guage i ws at about 5-7 psi but enginge when idling seems to have a miss of some kind engine rms drop 200-300 rmps on tack every second or two this norm and help whit these issues would be helpfull i would like to get the carbs set right now there set at 3 1/2 turns out and timing at 12 adv n i cant feel a power loss that is noticeable i can still burn the tires off lol thanks again pat
 
The base timing on that cam will likely want more initial advance. If it's stock pistons and heads, it will want LOTS more timing!
3.5 turns out seems to be a bit high as well,,,,,, I'm not certain about that, "I'm a Holley fan" but I think something like 2-2.5 turns would be more typical.
 
If the power valves are leaking or blown, the air screws will have no effect.
 
With dual quads you will have a different effect when dealing with the idle settings. First make sure the linkage is adjusted so both throttle levers move exactly at the same time and the throttle blades can seat in the bores of both carbs when the idle screws are backed off completely. 67 B body is right about the idle mixture screws being about 2 turns out. I'd start there, but keep in mind you have two sets of screws to deal with and everything should be even. It's likely you will have the idle speed screw barely opening the primaries of both carbs - maybe one turn each. The timing sounds about right and might want more initial.
 
what r the power valves there are new carb n intake i bought this summer y would they b blown or leaking? how much advance do u think i need i dont have stock pistons in the car they are forged pistons n its i new motor i built this summer
 
cam card gave me not specs on the timing it seems to run good and good power to burn off the my old tires then my new wheels n tires r going on but anyway how is the best way to set the rear carb been using a needle nose but cant get as acurate n not sure if im seating all the way in w needle nose just want the car to run n work properly w awesome power the cam i used is comp cam #21-672-4

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maybe a lose intake bolt that its seeping just enought air but w i spray w either has no effect on engine? go figure
 
Hard to say for sure on the actual amount of timing your engine will want..... Generally speaking, the MP 509 cam initial timing will be higher initial advance with less compression, and need fewer degrees of advance as compression goes up....
Do you know what the calculated compression is with this combination?
 
What makes you think you have a vacuum leak? Mixture screws controll gas, not air. If you screw them all the way in and it doesn't kill the motor then your probably not down on the idle circuit. Need to back off the idle speed screw and bump up the timing. Also as stated before, that cam probably needs more timing. Try around 15-17*. As Meep-Meep stated both carbs need to be set the same. A flow meter is nice to have.

Kinda hard to blow a power valve in an Edelbrock isn't it?
 
I guess I assumed the camshaft you were referring to was the Mopar Performance 509 cam. My fault....
I do however think they are pretty close "if memory serves".....
I once used the MP 509 camshaft in a 1969 440, with factory flat top pistons. It liked plenty of timing too,,,, I think it was somewhere around 18 deg initial advance. I didn't find out what worked best by reading, internet wasn't invented yet,,,,,, You can do the same as me by simply applying more advance "a couple degrees at a time" until it runs the best out of the hole...... Make sure you limit the max amount of advance once you get the lower end figured out. Get a good tach to measure when the full advance comes in as well.... You'll probably want it all in by 2600 rpm "give or take"...
 
meep meep i have both carbs set to open at the same time idle is 1000-1100 how do u check if the idle blades r seating corectley i willl advance more thought that was enought timing isnt 1000 enough idle? i turned idle screw up some since inital start up
 
do you know what your ign. timming curve is? how much total timming do you have? the vacum reading seems low to me. i personaly run much more initial timming with a total of 34 degrees mechanical i agree at about 18 degrees i think it would be happy then it might be easier to tune the carbs. also if you have been playing around for a bit you may have fouled up the plugs a bit as well. it happens sometime when you are dialing in a new combo with lots of carb, cam and not enough timming.
 
they were fould out i let dry over night n put back in or should i of repaced them? im using mp dist i dont know what the total curve is and im using old school timing light no bell whistles is seems to have good power though to burn off the tires

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is this why my enginge is dropping 2-300 rps like it flucuates like a miss? timming or plugs?
 
Every time I see the title of this thread I think... It was in the car last time I saw it. lol
 
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