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Yep its HEI . And I've got a bunch of that stuff hangin around. Weights stops this that . Never got to playing with them .
I thought I heard one time that limiting mechanical very low and having much more initial = go faster ?? Idk
Centerplate# ========== Weight# ===== Crankshaft Degrees*
...#346================139==============24*=====
...#349================139==============20*=====
...#361================139==============24*=====
...#363================139==============15*=====
...#364================139==============18*=====
...#365================139==============06*=====
...#368================139==============20*=====
...#369================139==============22*=====
...#370================139==============25*=====

...375=================41===============22*===== ALL ZZ series GMPP large HEI

...#375================139==============26*=====
...#383================105==============24*=====
...#389================139==============21*=====
...#393================139==============07*=====
...#398================139==============24*=====
...#399================139==============25*=====
...#400================139==============14*=====
...#401================139==============24*=====
...#402================139==============26*=====
...#404================139==============16*=====
...#406================139==============21*=====
...#416================139==============24*=====
...#417================139==============24*=====
...#422================139==============20*=====
...#432================139==============24*=====
...#438================139==============18*=====
...#444================139==============21*=====
...#445================139==============19*=====
...#446================139==============17*=====
...#449================139==============24*=====
...#451================139==============20*=====
...#452================139==============24*=====
...#459================139==============25*=====
...#462================139==============19*=====
...#467================139==============24*=====
...#469================139==============21*=====
...#470================139==============24*=====
...#481================139==============14*=====
...#482================139==============24*=====
...#483================139==============24*=====
...#485================139==============25*=====
...#486================139==============22*=====
...#508================139==============24*=====

Be aware that even if a set has the same overall degrees, the interface of curvature of center, and angle of
sliders on the weights may well have a very different curve between start point and total degrees limit.

This is not a full list, there are literally 437 different combo's, have fun in the next 3 years or so, checking them all out
there is NO full list.
Heres a post with some combinations if weights that might help you if you have some different distributors or weights avaible to get 18-20 deg mech advance.
 
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42* is not too much if the engine likes it.
Set total at 36* at 2800 - 3200. The initial will fall where ever, does not matter as long as it starts and stops like it should.
With no timing light advance until it starts hard and back down a little. Try starting again.
Then go to carb adjustment and back to timing. Back and forth until you get it.
 

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Discussion Starter · #25 ·
42* is not too much if the engine likes it.
Set total at 36* at 2800 - 3200. The initial will fall where ever, does not matter as long as it starts and stops like it should.
With no timing light advance until it starts hard and back down a little. Try starting again.
Then go to carb adjustment and back to timing. Back and forth until you get it.
Lol . That's all I ever did .
You're sayin pull the hose off VA and plug it .
Then put the light on it and run it up to around 3 grand and set it there at around 36 degrees and just use that for a baseline. Right ??
 

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When I test weights and mechanical advance I just leave the springs out to see what the total is, then I use the springs to fine tune how fast it comes in.
 

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Sounds like you’re on the right track. I have not been able to find a source for center plates and outer weights. Local auto dismantler likely has some old HEI’s on a shelf that you could “acquire” parts from.

For what it’s worth a 400 center plate and Moroso (made in USA) outer weights netted me 14 degrees mechanical advance which was perfect for my combo. Crane vaccum can set to full soft and limited to 10 degrees worked perfect. But my cam is a bit larger
 

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No source for weight afaik except if you buy a replacement shaft assembly for a hei. But I think its close to a new distributor. With a HEI you cant check the total without springs like on a point distributor it will over advance in a way that never happens with springs in place.
 
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Discussion Starter · #29 ·
Sounds like you’re on the right track. I have not been able to find a source for center plates and outer weights. Local auto dismantler likely has some old HEI’s on a shelf that you could “acquire” parts from.

For what it’s worth a 400 center plate and Moroso (made in USA) outer weights netted me 14 degrees mechanical advance which was perfect for my combo. Crane vaccum can set to full soft and limited to 10 degrees worked perfect. But my cam is a bit larger
Ok so bigger cam and a more performance application would perhaps call for less mechanical advance and more initial timing if I have that correct .
The application here is performance lite I'll call it in an old Square body chevy K2500 truck . Bout 5300 pounds unloaded. . 4.10 gear. 400 transmission.
Which combo that Ray has posted up there would you shoot for ? Wouldn't hold ya to it or nothin but lol Tryin to get a feel/ballpark.
And the moroso weights are available or no ? Center plate ?
 

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Discussion Starter · #30 ·
No source for weight afaik except if you buy a replacement shaft assembly for a hei. But I think its close to a new distributor. With a HEI you cant check the total without springs like on a point distributor it will over advance in a way that never happens with springs in place.
Might be easier to get another distributor I guess then maybe .
 

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Older distributors soometimes can wear the bushing/shaft at the top of the distributor housing causing the shaft to wobble. If this is the case it is causing the rotor to move inside the cap. Is the rotor center spring making good contact with the cap. I recently had a too short spring (almost not touching) and it acted like the 2 step was 1/2 working at 3200 rpm.
MSD HEI and they have a kit with weights, springs and bushings.
Source a used distributor and get the kit.
 

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I like to watch UTG, he's a character.
But go to the UTG video the OP posted in the first post of this thread and click to the 25 second mark.
"Vac advance has NOTHING to do with performance"
Then click to the 5:00 mark.
"Hooked to manifold VAC the distributor is doing the exact opposite of what you want it to do for performance"

Wait Uncle Tony, I thought VAC advance had NOTHING to do with performance?:unsure:
 

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Might be easier to get another distributor I guess then maybe .
I used a hacked up hei for several years with a screw limit to total advance an a crane stop plate for the vacuum advance might not been correct but worked for me.
 
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Discussion Starter · #36 ·
Older distributors soometimes can wear the bushing/shaft at the top of the distributor housing causing the shaft to wobble. If this is the case it is causing the rotor to move inside the cap. Is the rotor center spring making good contact with the cap. I recently had a too short spring (almost not touching) and it acted like the 2 step was 1/2 working at 3200 rpm.
MSD HEI and they have a kit with weights, springs and bushings.
Source a used distributor and get the kit.
You're sayin get a used MSD and a kit ?
And yeah idk about this distributor man .
The old motor blew and I just dropped the whole thing off to my machine shop/builder .
Handed him the new Mike Jones cam I had and told him to fix the motor and put it all back together. I'd was knockin.
Well it had a beat up MSD in it so I handed him an older GM HEI I had hangin around and that's what's in it now .
Somethins up . Now all of a sudden the .is at what feels like 40 percent power . No balls at all . It's not stumbling under load and it does fire right up and idles good but buts it lethargic big time . Can't get out of its own way lol If I leave it in low it takes way to long to climb to 3 grand even . It's a dog all of a sudden . I havnt gotten it back In the garage since but seems like it'd be ignition related .
Idk yet.

..
 

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Discussion Starter · #37 ·
I like to watch UTG, he's a character.
But go to the UTG video the OP posted in the first post of this thread and click to the 25 second mark.
"Vac advance has NOTHING to do with performance"
Then click to the 5:00 mark.
"Hooked to manifold VAC the distributor is doing the exact opposite of what you want it to do for performance"

Wait Uncle Tony, I thought VAC advance had NOTHING to do with performance?:unsure:
I agree on both points. He's cool. Like watchin but he's a few degrees off on some subjects I think lol. But hey who knows it all?
Raise your hand
 
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