Holley tuning advice.

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1967formulaS

1967formulaS

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Hi guys,
I've got a new 850 vac sec holley and put it on my 440.
The 440 is pretty stock but has the 383 closed chamber early heads and victor 440 intake. Not sure what cam is in it but it's a little lumpy.
Anyway I have set timing at 12 deg btc and my advance is 36 deg. I have the msd6al and my dizzy is a mechanical advance.
So I hooked on my vaccum gauge as I am having overheating issues (I'll post this issue separately) and the best I can get at idle is 15Hg at idle and around the same setting my advance. Before hand I was only getting around 10/11Hg.
I take her for a test drive and I have lost a fair bit of powerwhen I stomp on it, before I used the vaccum gauge. I was running the car a bit rich before I started.
I've got 73 jets on the primary side and 82 on the rear. Should I go up in jet size to 78 on the front to keep the same vaccum but get more fuel in?
 
No turn your initial timing up to 18-20 and get that dizzy curved and that may take care of it. run 34-36 total.
 
Sort out the timing, make sure you have no vacuum leaks, keep your carb and fuel cool and use a wideband O2 meter to dial in the carb.
 
sort the overheating issues out first, to be sure it's not timing related.
 
Retarded ignition timing can cause over heating. Get the timing sorted out first and then proceed.
 
First to the OP, please clarify, 12deg initial PLUS 36deg adv. ? Or 36 total? You'd be
lucky to wind past 5400 w/48deg ,esp. if those heads are actually providing real squish.
Second, I have only experienced one instance of over-advance overheating, but it
did occur on a cust.'s 350 double-hump headed chebby.He also set the timing by the ol'
vacuum gauge method. He came to the shop and asked me to check it out because it was
idling so fast he had the blades shut on the carb,AND it was getting hot. I checked it,the
marks,and tweaked it to 11 init/35 tot. and said it looked ok. Took it to a "chebby guy"
who said that was "way too much" and dropped it 5deg.Damn if he wasn't right,mind
you I'd done a set of "462" heads w/a street tunnelram on a 350 'bout the same time,
and he was running close to the same I set it to.Every set-up has it's own likes,and it
was prob. smaller cammed w/ nearly the same CR, so 11/35 was too much for HIS.
Just food for thought.. :coffee2:
 
I'm not much help in tuning. But the best Holley advice I got was to put the Holley back in the box and buy an FI TECH system.
 
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