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Discussion Starter · #1 ·
Thanks to a lot of advice from this site, I finally put together a 350 with RPM heads and cam, Holley 600CFM, stock HEI, headers and TH350 with 2600 stall. Got it to run and broken in. I can't seem to tune it right. Edelbrock recommends initial timing of 10-12 degrees. It won't even run at that setting. Idling at 1000rpm it still runs pretty sketch even at 18 degrees. They also recommend about 32 degrees total timing. If I set it at 32 degrees, when I drop the idle down to 1100 or so it doesn't want to run. What timing are you guys with this set up running?
Also, what kind of vacuum are you getting? With the guage on and other vacuum ports plugged, I get about 6 on the high end. Tuning air fuel mixture doesn't take it any higher.
Finally, it knocks intermittently. Briefly playing with the timing didn't seem to make a whole bunch of difference. (I used the 64 cc heads to get about 10.2:1 compression; the gas is a mixture of old 87 octane and new 92 octane, so I hope once the old gas is out and it's running pure 92, this won't be a problem)
I hope you guys with similar setups can help me out of this. Thanks
 

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When I cover the carb with my hands or a towel, about 2-3 seconds later the engine falters and wants to die. Also, spraying around the edge of the intake with carb cleaner doesn't do anything. Correct me if I am wrong, these things point against a leak. Is there any other way to tell if there is a leak?
 

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Have you run the HEI before putting the combo together?

Don't know if this is related, but on my 71 Chevelle (383 with the "RPM package" and 750 holley VS), the car would not run (idle) very well, until I replaced the factory resistive wire (from the fuse box) with a "regular" wire...But, I am running a Ballast Resistor and a Mallory Unilite distributor...I can't remember if you have to do that with an HEI...somebody else would probably know for sure...

Anyway, I have my initial timing set to around 16 degrees and the idle likes to be around 1,000 rpm or so...my vacuum is around 12 in or so at idle, which is about the most that can be expected with this cam...

The gas may have alot to do with it too....My car sits for long periods of time (hopefully no more after I get er back up though) and it always seems to run crappy for awhile...Use some rubbing alcohol (pref. the 90% stuff) in the gas tank (it's the same stuff as the "gas dryer"), to remove moisture, etc...



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I work to live, but make money for fun...when am I gonna start having fun?

John's '71 Malibu 383
 

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BTW - you may want to really consider going with a slightly larger carb...a 600 would seem like a restriction on this combo...I've had pretty good luck with a 750 vacuum sec. Holley on mine...but, do need to get it "tuned" still
 

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I'm running the RPM combo with iron Bowtie heads. The engine runs hard with lots of timing and dosn't ping, but it runs hot. When I back off the timing it runs at a solid 180 but dosn't have the low rpm power.
BTW my cam is installed 4 advanced for better vaccume 14 at 850 idle.
I can't give you my timing numbers because my balancer apparently spun and iv'e been doing it by feel.

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Rob Mirabile TC #1079, ACES #4387
"If You Don't Drive It-Sell It"

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67 Malibu Conv (always under construction)
64 Lemans Conv, Building for my brother-in-law
 

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A long shot but do you have the correct damper on it? Couldn't get my stuff to run because the damper was an early model on a late block. The TDC marks were way off.
 
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