RPM drop and electric fans!
A few things need to be addressed:
1) You need a higher output alternator. Most alternators are tested at room temp. A typical unit loses 20% efficiency at operating/underhood temps. 70A nominal output isn't nearly enough. With two electric fans, MSD ignitiin, headlights, fuel pump etc. I was melting the varnish off of the windings on a 95A Powermaster. Do ensure that yoour operating RPM is within spec (i.e. <18k RPM). Powermaster sells a larger pulley for higher rpm apllications. A 5.5" crank pulley will also help keep the RPM down.
2) #6 power cable is undersized. I've attached a chart to help select the cable length. If your car has a floating ground system make sure to use adequately sized cable for the entire length of the power run.
A few things need to be addressed:
1) You need a higher output alternator. Most alternators are tested at room temp. A typical unit loses 20% efficiency at operating/underhood temps. 70A nominal output isn't nearly enough. With two electric fans, MSD ignitiin, headlights, fuel pump etc. I was melting the varnish off of the windings on a 95A Powermaster. Do ensure that yoour operating RPM is within spec (i.e. <18k RPM). Powermaster sells a larger pulley for higher rpm apllications. A 5.5" crank pulley will also help keep the RPM down.
2) #6 power cable is undersized. I've attached a chart to help select the cable length. If your car has a floating ground system make sure to use adequately sized cable for the entire length of the power run.