No --- As Todd stated -- that only works at drag racing where you're able to shut down after a WOT run....


There are also ways to read timing on the spark plug "strap"... by where it changes color. The color change needs to be a line right across the apex of where the strap makes the turn. But now we're getting really old skool in the pit dyno.


Hope the distributor is the issue -- certainly points to an issue.

What color bushing you running? I would think BLACK.... which would be the 18* stop bushing... and with good heads and good fuel your total timing should be maybe 34 to 36* all in at 2500 to 3000 rpms??

Going with the blue bushing which is basically the one that comes with the distributor and then running the blue springs. I think full advance kicks in at 2900? Have to recheck but wanted to say thanks for the help buddy.
There is a mushroom top with a stud that the weights slide over and the cap completely wore down, broke off, and them was flying around in the distributor. So glad I found out what cracked the distributor cap crack.

The STOP BUSHING is under the plate that the weights attach to... you can't see it from the top at all...

Just saying.

The two light blue springs should work well. There's a graph in the MSD installation manual that shows you all the combinations of springs and were they come in.

Blue stop bushing gives you 21* of advance total FROM the initial.... so to get 36* total - your initial has to be set at 15*


As usual -- I write this stuff so OTHER GUYS that are reading these threads -- and don't know -- can read 'em and see what we're talking about.

Got it. Thanks Greg. You cant see the bushing because its recessed in the plate and covered by the lock nut that secures it in place but I figured out which bushing was in the distributor by looking at the one that wasn't in the kit. Wasn't sure what to set initial timing at but shooting for 32.5* total so looks like I'll be looking for 11.5* initial.

I found that my engine needed all the initial advance I could get. It cleans up the plugs at idle, better cold idle performance, and improved low speed drivability. I know you have a mechanical cam. I'd run the biggest bushing. I actually had a custom bushing in mine that would render 24 degrees initial with 34 total.

Best power was at 32.5* on the dyno? Didn't think your 23* heads were that efficient...

Going with the blue bushing because that's what we dyno tuned the engine with. You cant really tell if your running the right jet sizes in your carb when dyno tuning because you don't have the air cleaner on and the temps are a lot cooler which means the carb is getting fed cooler, cleaner air. With air cleaner on and in 90* plus weather at the track air intake and quality changes. The plugs have had the same light charcoal look from the last time I looked at them which means I am getting a bit to much fuel but didn't bother changing jet sizes in the carb because I want to play it safe and splash a bit more fuel in there but this next time around I'm going to drop a couple jet sizes and see how the car feels. I'm running 84's in the secondary side now but cant remember what I'm running on the primary side.

Yup. Good point though.

Yeah that motor isn't going to like 10 degrees initial... and the rule is always -- the most initial advance you can get without having the starter motor struggle too much or you get engine kickback...

Stock baby cam no compression motors in Buicks idle at 10*'s....


If you ran the black bushing --- that's 18*'s... so you'd end up with 16* initial and that motor can handle 16* initial easy....

You're probably idling around 900+ RPMS is my guess...

I think the Mustang is up around 1200+ and then it barely idles... Sounds like a thrashing machine.

In the old drag race days we'd run a lockout and just dial in the total timing and lock the distributor... then we'd add a coil cut off switch so we could spin the motor around without any spark until she was spinning good - then hit the switch and WHAM! She's fire off good! LOL ---- You need one of those set ups!!

Thems some pretty good heads! :thumbsup:

I think Rob's old dinosaur heads made best power at like 48* :lol: