Re: 396/375 hp/motor issues
 

Last time I had a car with that Petronix in it it ran pretty much as you are describing. It was in the car when I bought it. I went to auto zone, paid about $55 for a rebuilt single-point distributor and the AMX instantly ran perfect. Also picked up about 800 RPM.
Pull one plug wire at a time, ground it and see if you have spark out of all 8.

Re: 396/375 hp/motor issues
 

i will give it a try Jeff.thanks...with the timing light hooked up ,timing mark it is steady for about 5 or 10 seconds them its instantly jumps about 20 degrees.starting to make altittle more sense.

Re: 396/375 hp/motor issues
 

Me too-went through 2 of those junkers then bought a ford dura spark dist to power an msd box-cured months of frustration! now I just say no to pertronix

Re: 396/375 hp/motor issues
 

Chris - try swapping distributors and see if the problem goes away

Re: 396/375 hp/motor issues
 

changing distributors this weekend will let you guys know what happen...

Re: 396/375 hp/motor issues
 

I have used the Pertronics conversion for years on my boat. It has worked perfect. I doubt that is your problem. Google the wiring for your unit online. I cant rember but I think you have to eliminate the ballast resistor. If the ballast resistor is still in the system that could be causing some issue. Also some ignitions used a resistor wire. Run new wiring to the coil and pertronics unit.

Re: 396/375 hp/motor issues
 

The way you say your timing is jumping around,it sounds like ignition control/box problem.
I have used alot of pertronix on restoration projects have'nt had any problems,I use ignitor 3 has protection circuit and built in adjustable rev limiter,pertronix tech line has always been helpful when I have called,oddball installations, I would probaly give them a call.
I keep a hei w/wires so I can test and elimnate whole ign. system@ one time then have hei setup for msd so can determine box or dist.
Don't take for granted that any part can't be or go bad.
Mike Taylor 3601

Re: 396/375 hp/motor issues
 

Definitely check out the ignition as noted above. As a last resort, the carb to intake, or intake to head gaskets could be leaking vacuum.

Re: 396/375 hp/motor issues
 

hope to change out distributor tommorrow...changed the advance springs in the current distributor from light to medium to heavy.....light is just simply to light and a great deal of difficulty cranking.heavy is ok ,but slow gettin to the desired timing mark from the dyno tuning ,tried the medium spring ,but when timing mark was set at the 40 degrees under a load,the intial timing at idle was just too low and the car ran crappy...hopefully the distributor change wiil do the trick..the 396 nova has 11;5;1 compression .via purestock drag rules... and a msd 6a.

Re: 396/375 hp/motor issues
 

try eliminate msd box had one bad on customers car,had trouble starting and timing did weird stuff,was trying to get running could'nt twist dist to get running enough to even get light on it.
Mike taylo