centrifugal advance curve MSD Distributor

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68barracuda

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I just installed a MSD pro billet part number 8534.
I swapped out to the light springs but did not change advance stop bushing because I am having a little trouble understanding why I should change it.
I set my timing at 38 degrees with the lightest springs and the car rocks, I'm just wondering if it would run better with the red as opposed to the blue stop bushing or should I go the other way ?
choices
red- 28
silver-25
blue-21
black-18
anyone have a setting that worked well in there 10/1 with ross flat tops
Block was decked cleaned etc..
J headed with 2.02 1.60
mild bowl ported heads
484 comp cam that comes in around 2500 rpm
850 double pumper
The motor should be around 400hp or so the way its set up
Im useing a 727 trans and a convertor that flashes around 2800.

cuda2.jpg
 
Here is what I have in my 360/727/2800. Same dizzy as you. I have 16 initial timing and 34 total. I used the springs that allowed for all the timing to be in at 2500. I used the black bushing for 18 degrees of mechanical advance. I have had more than one person scream when I push the go pedal.

My engine is a magnum headed LA with 10.58 to 1 compression. I have somewhere between 425 and 450 HP.

I would say advance your initial timing until you start to ping, then back it off 2 or 3 degrees. Then set your mechanical timing to somewhere around 33 to 35 total. I don't think you want your total timing to come in before about 2500 as that is where your cam is starting to work.



Jack
 
the stops are all about the total curve. whats your initial timing like? i run my dart at about 18 to 20 initial and 35 total. the springs make the curve come in faster or slower and the stops is the total curve. if its a street car your better off with total coming in at about 2200 rpm.


in my 360 total is set at 35* at 2200 rpm. if i remember correctly i have the red stop in the dist and initial is close to 20*
 
I'm at 16 initial and 38 total at 2800 rpm with the blue bushing.
"I started out at 36 and the launch was sluggish" I haven't tried changing the bushing but the car spins the tires up all threw first with no detonation.
Idle is set at around 750 rpm.
 
I would shoot for total of 35 or 36 by 2000 rpms on a street car, Its always total on a hipo car its just a matter when that mech timing comes in at at full advane, no ,car will still start fine, Ive done it this way and that 65 degrees advance will hit ya in the seat of the pants, converter stall doesnt matter
 
right on abody joe and if your running ,ugh,vacuum advance you should be fully in by 2200 and have mech advance set at 35 degrees or 36 degrees with spark advance added you should have 53 degrees on the light,if not ya gotta use a hexhead screw and carefully stick it in the vac. pot to get proper degrees, thats why I like m.p stuff, its easy, simple to install, simple to understand. I run the msd on my 10 second dart but if I had the choice I would have used the m.p with race curve tach drive dist.and chrome box I got the rev limiter, line lock, transbrake ,the exp dedenbear delay box and now I wish I would have just kept it simpler as im going to convert this car to street soon as money allows,
 
The proper way to set the distributor up is to find the initial timing your motor wants first. The way to do this is to start with the factory initial timing setting and continue to add timing in 1 or 2 degree increments while keeping the idle speed the same (that is readjust the idel speed after each change in timing) until you obtain peak manifold vacuum. You may wind up with 20 degrees or more and if the engine wants to kick back against the starter when starting you will need compromise on the ideal setting and back off the timing until it doesn't unless you want to install a timing retard for starting.

Once you have established the initial pick the stop that the sum of the timing stop and initial adds up to 35-36 degrees.

No vacuum advance on that distributor so no work there. To do any better than that will require many trips to the track or time on a dyno.

I noticed you say you are using an 850 double pumper. That is way to much carb for anything but a very hot race only small block and will be real tuff to dial in for decent street manners. Based on your specs a 650 double pumper would be more appropriate or a vacuum secondary around 700 cfm.
 
Thanks for the info. The 850 works excellent on my set up. as well as the 38 degrees. Car idles fine and launches as well as my Drag car that runs 10.0 . All I was really interested in was the info on the advance stop bushing selection.:read2:
 
its always total here and on a street rod its fully advanced by 2000 to 2500 max here, but, different strokes for different folks
 
i run the black bushing with 35 total so my initial is @ 17. i think i am running 2 light blue springs.
 
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