The ZZ3 HEI distributor with MSD coil in the 396 is acting weird. When I run the RPMs up to check total advance with the vacuum disconnected, it starts jumping around. Then, when I let off of the accelerator, it jumps about 10 degrees - remember, this is with the vacuum advance disconnected.

It never really has been as steady as it should be, I would guess. I checked it over for anything obviously amiss when I went through my winter changes, everything seemed okay. I did change from a Crane HI-6 to an MSD Digital 6 Plus, and from a Performer RPM Air Gap to a Holley Strip Dominator. Otherwise, same coil, wires, etc. Both last year and this, though, the engine doesn't want to rev over 6200, but the cam is supposed to be good to 6800 and the Air Gap to at least 6500, and the Strip Dominator a lot more, of course.

I haven't been impressed with the Strip Dominator, so I'll probably put the Air Gap back on, and probably go back to using E85. While I'm at it, I think I need to address the ignition problem as well. Track times have been all over the place - not good for bracket racing.

 

Valvetrain weak? Springs not strong enough anymore?

 

I've wondered about that with regard to the reving issue. They're 4 years old, not even close to their advertised lift capability, but that's something to consider. One possible issue is that I didn't get the Comp retainers with the 916 springs, the guy who assembled the heads (and knows what he's doing) didn't mention any problem.

That wouldn't affect the ignition timing, though.