MSD Advance Curve Question

[rmorman]

Short background:
I recently went to a chassis dyno to help me set my carburetor as I was having problems with it being rich. According to their sensors, the fuel mixture seems to be pretty good and I have great throttle response. During the procedure, one of the guys who worked there recommended that I replace my Distributor cap on my MSD 8555 as the springs that hold the cap down were extremely worn. What I had looked like the “2 piece” ford style cap. The guys at the dyno shop recommended I replace it with the MSD 8433 & MSD 8467, which I did. Now the motor is VERY sluggish when I push on the throttle and pops and snaps (especially @ low RPM). It also tends to backfire if I “snap” the throttle too quickly. Not a great trade from my old cap. I have managed to adjust the timing a bit to help, but it is nowhere near drivable yet. I have purchased the MSD 8464 kit and had a couple of questions

Right now the springs are both the light silver and the bushing is the black one. The engine is at 14 initial & 37 total. When we have the timing light on it, the total timing is VERY erratic. Any thoughts on how to settle it down a bit? I heard this could be due to the digital gun? Any truth?

Here are my motor stats:
383 Stroker
Chet Herbert cam (.499-.502, 223deg – 234deg @ .050, 108 L.S.)
Victor Jr intake
Holley 750 DP
10.5:1 compression
92-octane fuel.
Max torque was reached at around 4000 RPM according to the dyno
Max rpm 6200
1979 Monte Carlo
95% street & 5% track driven
MSD 6AL, Blaster 2 & 8555 dist
Dart Sportsman heads 200cc, 64cc chambers, 2.02-1.50
2400 RPM stall
The motor runs about 190F temp.
Idle is 700 - 750 RPM
The motor doesn’t carry a large amount of vacuum
The MSD box is wired directly to the battery

At 14deg initial, my mini starter doesn’t seem to have any trouble turning the engine over & I don’t have any engine kickback. However, I have dieseling (run-on) when I try to turn the engine off and some sluggish throttle response as well as backfiring when I step hard on the throttle. I haven’t driven it since I changed the cap to see if I get a pinging under load, as the thing just isn’t even close. (I also just replaced the alternator the same time I installed the new cap as the alt was weak.)
What spring/bushing should I run (or at least start with)? What should I set my initial/advance timing to as a starting point?

HELP!

Thanks,
Russ

 

[JESSE]

here's my quess, i think you may have crossed some wires. it,s real easy to do .. if it was me i would check to see were my number 1 was at by pulling the plug and bringing the piston to tdc to check to see if the wires are in the right order 18436572 clock wise rotation.. on my distributor i used the lightest springs so i could get 36 degrees advanced all in at three thousand rpm,, i don't use the vaccum advance and don't care what the timing is at idle, i just adjust the carb to idle at about 750 in gear..now i'am not saying you should do this!! it's the way i do mine and i don't have any problems with detonation and my compression ratio is 11.1 i drive my car on the street and interstate and drag strip ..i hope this info will help you sort out your problem..jesse

 

[rmorman]

Thanks for the help. I will double check the wiring, but the ONLY thing I changed was the cap & rotor (the MSD has been on the car for 8 yrs and working fine until I put a new cap and rotor on). I'll double check where the rotor is at TDC & see if I got off 1 spot on the cap. I did double check the firing order & that seems fine.

 

[JESSE]

when you pull your cap and make sure the rotor pointer is not broken and pointing off to the side i have seen this happen...jesse

 

[rmorman]

I pulled the cap off over the weekend & the rotor is still in new condition. I'll double check, but I'm 95% sure it is still good. Thanks!!!