I finally had my car running great. I took it out for a drive and noticed my voltmeter dropping. My alternator died If I didn't have a deep cycle battery I wouldn't have made it home. Now my car runs rich and has a rough idle. Could the voltage problem damaged my MSD 6al box? Or should I look somewhere else?

 

Need to know more about your car: year, engine, induction system, other modifications, etc.

 

IT's a 355 forged internals, 11:1 pistons, Edelbrock performer rpm heads, edelbrock victor jr intake, proform 750 dp, msd 6al box, hei distributor.

When the alternator went out my fans died and it overheated to about 240* so I thought maybe a warped head. I did a compression test all were between 185-190psi. It did have a weak spark because all of the plugs were black. It has a miss at idle and I can't find it. I checked for vacuum leaks found none. I thought maybe running with too little voltage to the msd box may have damaged it.

I have a comp cams mechanical cam, 555 lift straight across 306 duration. valve lash at .022. I only have about 7ins of vacuum which i guess is because of the cam.