Need timing help

[blue 66 charger]

Trying to get my timing dialed in on my 440, have a firecore electronic distributor, I set it up at 16* initial and 36* total but I don't know what to set the vacuum advance, when hooked up I can't whack the throttle without it hesitating and down the highway I thing it's getting too much with the occasional backfire when going from light throttle to no throttle, and even a couple times would stall out of nowhere yet fire right back up when I hit the key. What's the best timing setups and vacuum advance (if used or not at all) for a 440 bored .060 over, stock cam, single plane intake, long tube headers and 750 carb.

 

[pnora]

Sounds like you have carb issues and not timing. Better start with checking the accelerator pump squirt and float levels. What carb are you running?

 

[blue 66 charger]

Sounds like you have carb issues and not timing. Better start with checking the accelerator pump squirt and float levels. What carb are you running?

Holley 4150 750cfm

 

[RJRENTON]

Holley 4150 750cfm

Isn't the Holley carb you note, a model 4160 with a secondary metering jet plate not a 4150 with removable secondary metering jets. The "original" model 4150, R-3310-1 had secondary removable metering jets, down leg booster venturi assembly and made 780 CFM, not 750 CFM. What you have must be a -2 or -3 model.......???.....just curious......
BOB RENTON

 

[RemCharger]

Could be a 4779 DP

 

[RJRENTON]

Could be a 4779 DP

A Holley Double Pumper carb is significantly different in design....not necessarily better, just different. It has 2 accelerator pump assemblies an NO secondary vacuum diaphragm assemblies. Do you have the R-numbers??.......
BOB RENTON

 

[blue 66 charger]

A Holley Double Pumper carb is significantly different in design....not necessarily better, just different. It has 2 accelerator pump assemblies an NO secondary vacuum diaphragm assemblies. Do you have the R-numbers??.......
BOB RENTON

Holley 0-82751SA Holley 4150 Aluminum Street HP Carburetors | Summit Racing here's a link to the exact carburetor I have

 

[threewood]

How did you set your timing up?
Vacuum unhooked and plugged?
Is your vacuum hooked to manifold or ported?

Unplug the vacuum advance, plug the port and go for a drive to see if the issue is still present.

 

[blue 66 charger]

How did you set your timing up?
Vacuum unhooked and plugged?
Is your vacuum hooked to manifold or ported?

Unplug the vacuum advance, plug the port and go for a drive to see if the issue is still present.

It was set up with the vacuum plugged. And it's set to ported, on a warm day it's got good throttle response without vacuum advance hooked up, It bogs when it is hooked up

 

[blue 66 charger]

But i was told it's bad for the engine to not have it hooked up to anything

 

[threewood]

When you set your timing, did you use a vacuum gauge? On your distributor, how do you set total advance?
On the vacuum advance can, are there numbers or can you limit the advance? I'm unfamiliar with Firecore distributors.

 

[blue 66 charger]

When you set your timing, did you use a vacuum gauge? On your distributor, how do you set total advance?
On the vacuum advance can, are there numbers or can you limit the advance? I'm unfamiliar with Firecore distributors.

On the firecore distributor it is adjustable but i left it at its factory setting. I do not have a vacuum gauge. I just used a timing light to atleast get the initial and mechanical advance set up

 

[blue 66 charger]

I know it has to be too much vacuum advance i just wanted to know how others have theirs set up to I can base it off that

 

[66 Sat]

I've got that exact carburetor on my small block (except in 650 size).

It's definitely more 'race oriented' compared to the Holley 600 V/S and Edelbrock 650AVS2 I had on there before.

Mine runs good but it's noticeably less forgiving at low speeds/rpms in traffic and is set up to run richer than a cruiser type carb. I've been able to increase my timing 2° with this carb and avoid detonation compared to the AVS2, presumably because of the additional fuel. But when I added the timing, I had to re-adjust the carb again.

What I'm getting at, is that the timing and carb tuning goes hand in hand. If your timing settings are based on your old carb you may need to add timing with the new one to get it to run right, and keep going back and forth a few times - timing/carb/timing etc until you're there.

 

[blue 66 charger]

I understand where ut getting but this is the first set up, the engine was first put together a couple years ago and only fired up first last year. But I'll get a vacuum gauge and go from there.

 

[blue 66 charger]

But with vacuum advance specifically, what should I be looking for so I get it set up correctly? That way timing is dialed in to then get the carb all set. I'm only 23 and very new to this kind of thing

 

[RJRENTON]

Holley 0-82751SA Holley 4150 Aluminum Street HP Carburetors | Summit Racing here's a link to the exact carburetor I have

Thanks for the information.......IMO....too big for street use, especially the double pump design. I would set your distributor to yield: 35 degree total advance, 15 degree static (@ idle), 20 degrees mechanical advance all in by 2600 RPM.....no vacuum advance both ported and manifold connections capped. Just my opinion of course.....others will disagree..........
BOB RENTON

 

[hunt2elk]

I run those Firecore distibutors and like them a lot. If you have the 2 weak springs in there, that would be allowing the advance to come in too quickly. I would also bump your total timing down to 32 or so for now. Saying that, it does sound like you have carb issues as well. All the Holley and Quick Fuel mechanical secondary carbs that I have are coming set up way to rich for street driving.

 

[RemCharger]

Isn't the Holley carb you note, a model 4160 with a secondary metering jet plate not a 4150 with removable secondary metering jets. The "original" model 4150, R-3310-1 had secondary removable metering jets, down leg booster venturi assembly and made 780 CFM, not 750 CFM. What you have must be a -2 or -3 model.......???.....just curious......
BOB RENTON

Could be a 4779 DP

A Holley Double Pumper carb is significantly different in design....not necessarily better, just different. It has 2 accelerator pump assemblies an NO secondary vacuum diaphragm assemblies. Do you have the R-numbers??.......
BOB RENTON

You're the one that for some reason assumed it's a 4160 VS. Must be 5 o'clock there..

 

[RJRENTON]

You're the one that for some reason assumed it's a 4160 VS. Must be 5 o'clock there..

Another unrelated and cryptic response......?????.....
BOB RENTON