Timing curves for MSD Digital E-Curve Distributor?

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69_340_GTS

69_340_GTS

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Can anyone recommend the best advance curves, mechanical and vacuum, to program an MSD Digital E-Curve Pro Billet Distributor? It’s in a 340 with 10.5 compression, 268°/.464” Comp cam, Eddy heads, 600 Eddy carb., headers. Right now it runs good with around 15° initial, 20° centrifugal starting at around 1000 RPM, all in by 3000 RPM. So I’m thinking "Curve F" , but I don’t know where to set the vacuum. Here are the available curves:
2v2EiLGbMxAYakF.jpg
 
My 340 is close to yours but I run a ported X head, little more cam and a 800cfm carb.
My initial timing is set at 16 BTDC and have 18 degrees of mechanical advance.
All in @ 3200 rpm
My engine has 14 inches of vacuum at 800 rpm idle.
vacuum advance is set to add 10 degrees @ 3200 rpm
16 int + 18 mech + 10 vac = 44 Total
My car is for street use and I burn 91 octane pump gas
Engine runs very well, starts nice, idles great and has never detonated.
If I make any change it may be to add more vacuum advance.
 
Last edited:
512Stroker said:
My 340 is close to yours but I run a ported X head, little more cam and a 800cfm carb.
My initial timing is set at 16 BTDC and have 18 degrees of mechanical advance.
All in @ 3200 rpm
My engine has 14 inches of vacuum at 800 rpm idle.
vacuum advance is set to add 10 degrees @ 3200 rpm
16 int + 18 mech + 10 vac = 44 Total
My car is for street use and I burn 91 octane pump gas
Engine runs very well, starts nice, idles great and has never detonated.
If I make any change it my be to add more vacuum advance.
Click to expand...



Just for the record, you have your vacuum advanced hooked to manifold vacuum and not ported vacuum or it wouldn't add timing at an idle.
 
yellow rose said:
Just for the record, you have your vacuum advanced hooked to manifold vacuum and not ported vacuum or it wouldn't add timing at an idle.
Click to expand...
Once again you are correct.
Manifold vacuum
I have not checked how much the vac advance adds at idle, probably 10 or more degrees, sure does make it idle nice.
My distributor was built/curved by FBO and they stated non ported full manifold vacuum
 
Last edited:
512Stroker said:
My 340 is close to yours but I run a ported X head, little more cam and a 800cfm carb.
My initial timing is set at 16 BTDC and have 18 degrees of mechanical advance.
All in @ 3200 rpm
My engine has 14 inches of vacuum at 800 rpm idle.

vacuum advance is set to add 10 degrees @ 3200 rpm
16 int + 18 mech + 10 vac = 44 Total
My car is for street use and I burn 91 octane pump gas
Engine runs very well, starts nice, idles great and has never detonated.
If I make any change it may be to add more vacuum advance.
Click to expand...

When does your mech advance start and how much by 2000 ?
 
mbaird said:
When does your mech advance start and how much by 2000 ?
Click to expand...
Unfortunately I do not have a plotted timing curve.
The distributor was curved by Don at FBO
Mine is a street application and I believe the curve comes in slow.
I had a MSD pro billet that I had set up way to fast of curve all in by 2500 rpm, that did not work. anything over 32* total it would knock like a *****. With my new FBO distributor the timing comes in slow all in 36* at 3200 rpm and no knock. Then the vacuum advance adds another 10* at cruise for a total of 44*and it never pings.
I would never thought it possible but it works.
and my fuel mileage went up
 
512Stroker said:
Unfortunately I do not have a plotted timing curve.
The distributor was curved by Don at FBO
Mine is a street application and I believe the curve comes in slow.
I had a MSD pro billet that I had set up way to fast of curve all in by 2500 rpm, that did not work. anything over 32* total it would knock like a *****. With my new FBO distributor the timing comes in slow all in 36* at 3200 rpm and no knock. Then the vacuum advance adds another 10* at cruise for a total of 44*and it never pings.
I would never thought it possible but it works.
and my fuel mileage went up
Click to expand...
That's some good info. I think I will try to duplicate it in the MSD.
 
I ask because I am trying to jet a QF 750 VS on a similar build and trying to figure out the relationship between timing curve and jetting This damn carb cant find an even ground for A/F. It goes pig rich to lean for anything below 2500 rpm
I’m thinking it might be timing related
I have recurved the dizzy for 16 initial and 18 mech advance + 17 vacuum.
I also ordered a new AVS2... lol
 
mbaird said:
I ask because I am trying to jet a QF 750 VS on a similar build and trying to figure out the relationship between timing curve and jetting This damn carb cant find an even ground for A/F. It goes pig rich to lean for anything below 2500 rpm
I’m thinking it might be timing related
I have recurved the dizzy for 16 initial and 18 mech advance + 17 vacuum.
I also ordered a new AVS2... lol
Click to expand...
I ditched my holley for an 800 cfm edelbrock
I could never get the holley to transition to part throttle
For my street setup the edelbrock was the answer and easy to tune
 
When I tried to set the secondary throttle plates I found the butterfly’s were uneven.
If I had one exposing enough transition slot the other would be covered! I think that might be one issue?
I ordered the 650 card 1906 because I want the drive ability for this 360 in the fastback .

I am also building a 69 340 4sp Swinger that has a 408 W2 solid roller motor with a Pro Systems custom double pumper and a Daytona Sensors digital ignition.
 
F or G would likely be fine. If it's an auto car, ideally, you want the timing in before the converter stall RPM. If it's a stocker style converter, not much you can do. 2500-3000 is a good range to play in.
 
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